This problem deceived me so hard, am I stupid? Factoring & quadratic formula, Reddit r/Homeworkhelp

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bprp math basics

bprp math basics

Күн бұрын

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@bprpmathbasics
@bprpmathbasics Ай бұрын
New mechanic just dropped!! 196-182*0.5=7!! Most Redditors didn't get this. r/unexpectedfactorial kzbin.info/www/bejne/d4LMeIOql7-iZqs
@beanureeves9650
@beanureeves9650 24 күн бұрын
wouldn't you do order of operations a.k.a. 196 - (mult first: 182 * 0.5 or 1/2) = ...not 7. 196 - 182/2 = 196 - 91 = 105
@JeremyLionell
@JeremyLionell 10 ай бұрын
Not understanding something doesn't make you stupid, you just didn't know it yet. Especially if it's math, it can be pretty difficult sometimes...
@narayandaschowdhury4425
@narayandaschowdhury4425 10 ай бұрын
Right! I learned quadric equation at 9th grade
@flaregod9563
@flaregod9563 10 ай бұрын
@@narayandaschowdhury4425 my uncle taught it to me in the 7th grade
@cacalightx
@cacalightx 10 ай бұрын
@@flaregod9563 claps for u buddy
@stevenhthe21st
@stevenhthe21st 10 ай бұрын
@@flaregod9563 Well, if you managed to remember or use it at all the next 2 years, cool
@yinnky
@yinnky 10 ай бұрын
imo there should be 2 different words for being stupid: for not knowing something and for needing more time (or being unable to independent of efforts) to understand something in everyday speech both are called stupid
@GIRGHGH
@GIRGHGH 10 ай бұрын
I know it looks harder but I find the formula way simpler to use. It's the same solution for every quadratic question and you just swap the numbers. Once I memorized it and got practice everything flowed out smoother and I never got a question wrong again
@pon1
@pon1 10 ай бұрын
Yes, best part is that it involves no guesswork, the formula just works :), but sometimes teachers will want you to use the other methods and factoring can be useful in other ways as well.
@Matik182
@Matik182 10 ай бұрын
I'm from Slovakia, and we didn't even be taught to use first method (by factoring), we directly were taught quadratic formula
@PRScrewdriver16
@PRScrewdriver16 10 ай бұрын
same
@MuhDog
@MuhDog 10 ай бұрын
The quadratic formula is very useful but it is also important to learn the completing the square method. This method will be required for putting quadratic equations from standard form into vertex form and for putting circle equations from general form into standard form.
@xxgn
@xxgn 10 ай бұрын
@@MuhDog Once you know the roots, you can use them as a way of completing the square. If you want this process to be more mechanical, you need to normalize the equation (i.e., set a to 1 by dividing by a) first.
@joshuahillerup4290
@joshuahillerup4290 10 ай бұрын
I almost always just use the quadratic formula to factor a quadratic
@Raihan_Badat
@Raihan_Badat 10 ай бұрын
Same
@Mathemagical55
@Mathemagical55 10 ай бұрын
I always calculate the discriminant b^2 - 4ac to determine whether it factorises or not. If it does then the square root of the discriminant is a hint to what the factors are.
@sploofmcsterra4786
@sploofmcsterra4786 10 ай бұрын
That's good, you should do that if you need to do it quick. But being able to derive the quadratic formula gives a much deeper understanding, and gives you a more flexible approach that doesn't rely so much on rote memory
@athrv._.
@athrv._. 10 ай бұрын
Do you know the middle term splitting method?
@Raihan_Badat
@Raihan_Badat 10 ай бұрын
@@athrv._. that’s one way to call the factorisation method
@d4TheViewer
@d4TheViewer 10 ай бұрын
Original Question: 2x^2 + x = 6 You can either factor (if possible), or use the quadratic formula. Before we try the quadratic formula, let’s see if the equation factors. Factor: 2x^2 + x = 6 2x^2 + x - 6 = 0 Because the leading coefficient is ≠ 1, we have to find a number that multiplies to be a * c: a = 2, c = -6 2 * -6 = -12 And that adds to be = b: b = 1 Those numbers give us 4 and -3 (4*-3=-12, 4-3=1) (2x^2 + 4x) - 1(3x - 6) = 0 2x(x + 2) - 3(x + 2) = 0 (2x - 3) (x + 2) = 0 Solve for X: 2x - 3 = 0 2x = 3 x = (3/2) Check: 2(3/2)^2 + (3/2) = 6 2(9/4) + (6/4) = 6 (18/4) + (6/4) = 6 (24/4) = 6 6 = 6 ✔️ (3/2) is a valid answer Solve for X: x + 2 = 0 x = -2 Check: 2(-2)^2 + (-2) = 6 2(4) - 2 = 6 8 - 2 = 6 6 = 6 ✔️ -2 is a valid answer Final Answer: x = (3/2), (-2)
@skwbusaidi
@skwbusaidi 9 ай бұрын
This is easier than tik tok method because you do not have to guess. Only think of two numbers that thier product is ac ( here -12) and thier sum is b ( here is 1) . The answer in this case -3 & 4 and use this to split the factor of x . The good thing is that the order does not matter and it will work. I will use diffrent order 2x^2-3x + 4x-6=0 x(2x-3) + 2( 2x-3)=0 (2x-3)(x+2)=0 x =3/2 , x =-2
@ToppledTurtle834
@ToppledTurtle834 9 ай бұрын
Still don't know why it's kadebthis difficult. Just say itvis equal to x^2 +0.5x = 3 = (x + 0.25)^2 - 0.25^2 = 3 = (x + 0.25)^2 = 3.0625 = x + 0.25 = sqrt( 3.0625) or - sqrt( 3.0625) So x = 1.5 or x= - 2
@KiraKage
@KiraKage 9 ай бұрын
Nice use of Chat GPT 😅
@TheKnowledgeOfScience
@TheKnowledgeOfScience 25 күн бұрын
​@@KiraKage yes 😂😂
@GaminghunterYTOfficial
@GaminghunterYTOfficial 16 күн бұрын
I did it that way
@dominikdanda7863
@dominikdanda7863 10 ай бұрын
I'm an upper year canadian engineering major and I watched this whole video. no idea why but Im glad these resources exist for others :) mathematical literacy is really important!
@enriquecubanito3788
@enriquecubanito3788 10 ай бұрын
😂
@metallsnubben
@metallsnubben 10 ай бұрын
Even if I already know how to solve the problems, I'm learning a lot about _how to teach/explain_ it!
@Cushiondude
@Cushiondude 10 ай бұрын
I did the same thing. I know how to solve this. I'm 31 and haven't been tested on this part of math in a long time, but I am thinking how this might help my younger sister who is learning this type of stuff currently.
@danielpark8245
@danielpark8245 9 ай бұрын
lmfao i'm a second year biomedical engineer and i have a dif eq exam in abt 50 minutes... i also have no idea why i watched this
@MightyBiffer
@MightyBiffer 9 ай бұрын
I have a masters in mathematics and I watched this whole video. The I looked in the comments and saw that I had already watched this video before and left a comment.
@HashimotoDatsu
@HashimotoDatsu 10 ай бұрын
Hey, I completely forgot about this! I just looked at it and thought it was -2. I'm glad I clicked on the video to check. It's been 16 years since I've thought about the quadratic formula. Still had the equation drilled into my brain lol. Great refresher!
@fabo-desu
@fabo-desu 9 ай бұрын
I’m not trying to shame you or anything, but how do you get that? Bcz I just got out of high school so these formulas are still really fresh for me. Again, not trying to shame or disrespect you
@HashimotoDatsu
@HashimotoDatsu 9 ай бұрын
@fabo-desu A lot happens in life after school and if you aren't using the knowledge and keeping those neurons freshly connected it can fade. I got my answer by solving it like a quick puzzle in my head. However, I always check to make sure I'm right because I know some things blur together. A good example is Pokémon Red Version. I can still recall where every Pokémon and invisible item is (even the Pokémon levels you can find in certain areas), but I recently got stuck for a couple of minutes in the Dark Cave without flash and ran into a couple unnecessary fights, which never happened a kid. Last time I played the Red version had been 20 years ago. Even though I remembered almost everything, there are pieces of memory that stay dormant until you have to re-access it. Once he mentioned setting it up as a quadratic equation, it clicked back for me. I just haven't seen a quadratic equation since 10th grade for pure math problems. A bit of physics in college as well, but I only took a semester before going into the Navy for Electronics Technician. You don't really need to know quadratic equations or Calculus to take electrical measurements, replace resistors and capacitors, or work on computers. Hell, these days I do IT work. That's why I try to keep myself sharp when I see things like this. If I didn't, I would never think about it. Hope that makes sense! I was pretty on point with stuff from highschool until about 27ish. I'm 33 now.
@DarkDragonRus
@DarkDragonRus 9 ай бұрын
That's pretty intuitive, you try to gor for integers, 1 is too smal, 2 gives you 8+2=6 so it's too big but then you see that just changing +2 to +(-2) makes it's right and it doesn't matter if the number is negative if it's in even power since - x - is + as well as + x + is a + too.
@Nachtschicht1
@Nachtschicht1 9 ай бұрын
@@DarkDragonRusThat's exactly my thought process after seeing the preview-picture, but it only really works with relatively easy numbers, so I'm still happy to have seen the video to refresh a little bit of math-knowledge.
@JaxonRabbit
@JaxonRabbit 8 ай бұрын
Same, same, 15 years since I've had to do a quadratic equation but I love maths and use probabilities and factors every single day of my life but going back to the hard stuff, really wrinkled my brain for a minute, feels good.
@rievenailo
@rievenailo 10 ай бұрын
I just realized that having a 4 year old means i have roughly 10 years to relearn this stuff to help her with her math classes
@grey5751
@grey5751 Ай бұрын
That's a realization to be proud of, shows what matters to you. Thank you for sharing.
@meijuta
@meijuta 10 ай бұрын
Its always slightly impressive that he can switch between markers with one hand
@Tantalus010
@Tantalus010 10 ай бұрын
That was my big takeaway. I mean, I already knew the math, so when I noticed that he was writing in two different colors with the same hand, that became my focus for the rest of the video. He's slick, palming a second marker so that he can quickly switch like that.
@hypnodink
@hypnodink 10 ай бұрын
...while explaining the math.
@ZipplyZane
@ZipplyZane 9 ай бұрын
bprp literally stands for "black pen, red pen." Those are the colors he most often has in one hand.
@jules1593
@jules1593 9 ай бұрын
oh my god hahaha i was just thinking the same thing... ive never seen a teacher that does that so seamlessly
@PatClevenger0709
@PatClevenger0709 9 ай бұрын
I'm a 49 year old engineer and I watched the whole video. I automatically do the quadratic formula since it's just easier for me.
@drigondii
@drigondii 9 ай бұрын
I always have to solve for the quadratic formula because I can never remember it, so I default to factoring. I'm a 32-year-old engineer 😅
@trollfacereaction-f3x
@trollfacereaction-f3x 4 ай бұрын
√49😂
@JimmyMatis-h9y
@JimmyMatis-h9y Ай бұрын
cheating! lol
@johnbartholf777
@johnbartholf777 10 ай бұрын
I wish this channel had been around when I was taking these classes. I am genuinely grateful there are people out there who love math and can do math. I'm not one of them. Godspeed, everyone else!
@Tobiichi
@Tobiichi 10 ай бұрын
I click these because I'm interested in the maths, then I get completely mesmerised by the effortless pen juggling. Every, single, time.
@orisphera
@orisphera 10 ай бұрын
Shortcut: the even term can't be the lower one. If it was, the middle term would be even. If the product is irreducible, so are the terms. Whenever a and c have a common factor, you should put it in the x-term of one and the 1-term of the other. (If it's in a power, you shouldn't split it. This only applies to common factors. If there are multiple, you can put one in a fixed place and consider cases for the others. Or you can use the formula)
@Dumpy332
@Dumpy332 10 ай бұрын
The way I used factor method is to calculate ac and guess its factors which sum to b. In this example , I found ac = -12. I then tried to think of factors of -12 which adds up to b=1 . The factors were found to be 4 and -3. 2x^2 +x -6 =0 2x^2 +4x -3x -6 =0 2x (x +2) -3(x +2) =0 (2x -3)(x +2) =0
@Guido125
@Guido125 10 ай бұрын
This is exactly how I solve it as well. Seems much simpler!
@DriverDad58
@DriverDad58 10 ай бұрын
After using the "guess and check" method for years, I learned the method @Dumpy332 outlined here. I HATE guess and check for ANY math. An algorithm that always works is MUCH better. Having said that, I had a student that always used the quadratic formula no matter what, and I couldn't talk her out of it. She's a lawyer now so I guess it worked for her :) As an aside, I always tell my students that the difference between "hard" and "easy" is that you know how to do the easy stuff but don't know how to do the hard stuff. At least I've found that true for many, many things, even beyond math.
@Dumpy332
@Dumpy332 10 ай бұрын
Other way to solve is by completing the square which has no guesswork and is basis of quadratic formula: 2x^2 +x -6 =0 x^2 + x/2 -3 =0 x^2 + 2(1/4)x + 1/16 - 1/16 - 3 =0 (x + 1/4)^2 - 49/16 =0 (x + 1/4)^2 - (7/4)^2 =0 (x + 1/4 + 7/4) (x + 1/4 - 7/4) = 0 (x + 2)( x - 3/2) =0
@YabiHanaki
@YabiHanaki 10 ай бұрын
@@Dumpy332u divide 2 side to 2 xD. In my country we have one person trying to solve 1 math ex with more than 20 different way lmao. Math is crazy fr
@Duraludon884
@Duraludon884 10 ай бұрын
When I learned the quadratic formula, my teacher had us sing it to the tune of "Pop Goes the Weasel." As silly as it may have felt at the time, I guarantee none of us will ever forget "x = -b plus or minus the square root of b² - 4ac, all over 2a"!
@johnwalker1058
@johnwalker1058 Ай бұрын
Same. My eighth grade algebra teacher used the same technique to teach us the quadratic formula.
@pi_xi
@pi_xi Ай бұрын
There is a German rapper named DorFuchs, who makes songs about mathematics (he has a PHD in that subject). He also has a very catchy song about the pq formula, which is a simplified version of the abc formula after normalizing the coefficients.
@sacksj
@sacksj 10 ай бұрын
This channel is absolutely brilliant! I excelled at math throughout high school, did it at a University level to some degree and forgot how to solve something so basic. My mind was just substituting numbers but completely forgot I could go negative or fractions. Love your work!
@SecularMentat
@SecularMentat 10 ай бұрын
I love seeing the fundamentals as well as the hard stuff that's difficult to explain. If for no other reason so I won't forget how the basics are done. Keep up the great work BPRP.
@austinfu2102
@austinfu2102 9 ай бұрын
I equally hate all those teachers who just throw the quadratic equation to their students without explaining what is it, why is it and without introducing the concept of discriminant. The formula is just a big lump of algebra without those explanations. the discriminant which I usually call Δ, is the bit under the square root. Meaning Δ=b²-4ac. It is so useful as it tells you how many real root you should expect. If Δ>0, expect 2 real root, thanks to the ± in front of the square root. If Δ=0, expect only one real root and if Δ<0, expect no real root. This serve as a really good gatekeeper for your answer. and pkus, the formula is now as short as (-b±√Δ)/2. A bit easier to remember now isn't it.
@Llanchlo
@Llanchlo 3 күн бұрын
Absolutely. You should never give out the formula. Once students have basic algebra you introduce simple factorable quadratics, staring with those with integer solutions, and methods such as "completing the square. Once they understand how to do that they should be able to work out the formula by applying those methods to ax2+bx+c=0. Not all will master this but I guarantee that those who cannot will never need it !
@khavinajaysaravanan4771
@khavinajaysaravanan4771 5 ай бұрын
Here's how Indian students do it: 2x² + x = 6 (Bringing 6 from R.H.S to L.H.S) 2x² + x - 6 = 0 (Splitting middle term) 2x² + 4x - 3x - 6 = 0 (Taking 2x as common in the first and second term and 3 as common in the third and fourth term) (x + 2)(2x - 3) = 0 Hence, x = -2 (or) x = 3/2
@gameknowledgeandit8934
@gameknowledgeandit8934 26 күн бұрын
this is such a long way to do it and involes a lot of guessing in breaking the middle term. the best way to do it is either by this way or by simply using quadratic formula
@MarieAnne.
@MarieAnne. 19 күн бұрын
@@gameknowledgeandit8934 This is actually not much longer than factoring when leading coefficient is 1. For example, to factor x² + x − 6 = 0. we need to find factors of −6 that add up to 1. These are −2 and 3. so we get: x² + x − 6 = 0 (x − 2) (x + 3) = 0 x = 2 or x = −3 Similarly, to factor *_4x² − 5x − 6 = 0,_* we need to find factors of (4)(−6) = −24 that add up to −5 These are −8 and 3. so we split up middle term −5x into (−8x+3x) and get: 4x² − 5x − 6 = 0 4x² − 8x + 3x − 6 = 0 4x (x − 2) + 3 (x − 2) = 0 (x − 2) (4x + 3) = 0 x = 2 or x = −3/4 Using quadratic formula, which requires more arithmetic (and which I personally find more prone to minor miscalculations that can lead to erroneous results) we get: 4x² − 5x − 6 = 0 x = (−(−5) ± √(5²−4(4)(−6))) / (2*4) x = (5 ± √(25+96)) / 8 x = (5 ± √121) / 8 x = (5 ± 11) / 8 x = (5+11)/8 = 16/8 = 2 or x = (5−11)/8 = −6/8 = −3/4 And using the tic-tac-toe method shown in video, we get factors of 4x = (x)(4x) or (2x)(2x) and factors of −6 = (−1)(6) or (−2)(3) or (−3)(2) or (−6)(1), leading us to potentially having to check all of the following: (x−1)(4x+6) (x−2)(4x+3) (x−3)(4x+2) (x−6)(4x+1) (x+6)(4x−1) (x+3)(4x−2) (x+2)(4x−3) (x+1)(4x−6) (2x−1)(2x+6) (2x−2)(2x+3) (2x−3)(2x+2) (2x−6)(2x+1) Yes, the solution we need is 2nd on this list. But if we had to solve 4x² − 10x − 6 = 0 then the correct solution would be last on this list.
@gameknowledgeandit8934
@gameknowledgeandit8934 19 күн бұрын
@@MarieAnne. soo unnecessary checking . 😭 i dont have time, if you dont have calculator I'd still use quadratic equation
@programaths
@programaths 10 ай бұрын
2x²+x-6=0 We know that parabola are symmetric. So, for a well chosen "u", we have: f(u-x)=f(u+x) a(u-x)²+b(u-x)+c=a(u+x)²+b(u+x)+c -2aux-bx=2aux+bx (skipped same terms) -4aux-2bx=0 Let set x=1 to solve for u and simplify. 2au+b=0 u=-b/2a So, -b/2a is where our vertical axis of symmetry pass. Now, our solutions have to be on either side of -b/2a or -1/4 2x²+x-6=0 => x²+x/2-3=0 (x-a)(x-b)=x²-(a+b)x+ab ab=-3 a+b=-1/2 (-1/4+t)(-1/4-t)=-3 1/16-t²=-3 t²-1/16=3 t²=49/16 t=7/4 -1/4+7/4=6/4=1/2 -1/4-7/4=-8/4=-2
@TheAwesomeAnan
@TheAwesomeAnan 10 ай бұрын
I am in 8th grade and I did it exactly how you did, but just a correction. 7/4-1/4=6/4=3/2 not 1/2.
@programaths
@programaths 10 ай бұрын
@@TheAwesomeAnan That was the most complex part ^^
@TheAwesomeAnan
@TheAwesomeAnan 10 ай бұрын
@@programaths lol
@epikherolol8189
@epikherolol8189 10 ай бұрын
​@@TheAwesomeAnandamn in my country 8th grade has pythogoras theorem and comparing numbers... Like ratio and % We learnt parabola and symmetric functions in 11th
@programaths
@programaths 10 ай бұрын
​@@epikherolol8189Same in Belgium and we are the 13th in PISA ranking. We can solve problems like "By operating only on denominator, augment 5/7 by its 2/3". Ratio are much more complicated than quadratics. That's because you can get away with one formula for quadratics, or using the above or completing the square. On the other side, proportions requires a variety of concepts and more adaptability. 5 machines do 5 widgets in 5 minutes, how many times do 10 machines to do 10 widgets? To make a glass of grenadine, you need 1 volume of sirup and 7 volume of water. How much sirup do you need for 1L? One person takea 30 minutes to do a task. Another person takes 40 minutes to do a task. If they work toghether, how long would it take for them to do the same task? Convert 100kph in mps. A person walking at 5kph on a 100m long conveyor belt. He takes 5 minutss to go back an forth. How fast is the conveyor belt? And also, look for a video about how to calculate base tax in Belgium that I posted on my channel. You can see that each problem need a different way to approach it and I didn't even touch the geometric aspect. (Thales and similar triangles) We push quadratics down the line to do them at the same time as more advanced algebra when we study function (limits, assymptotes, derivatives...)
@NicholasAguirre-j4k
@NicholasAguirre-j4k 10 ай бұрын
I always found the cross method to be my go to for solving quadratics, wherein you draw a little X and on the top you multiply the constants a by c, and on the bottom you put b. Then you ask yourself what two numbers multiply to give you the top, and at the same time what two numbers add up to give you the bottom? in this case, we would have 2x^2+x-6 = 0, so the top would be -12 and the bottom would be 1. You can just go through all the various factors of 12 in your head (sometimes if the number is large it can take a bit), but the only combination that works would be -3 and 4 (-3*4=-12, -3+4=1), and that would be your -3x+ 4x terms, which you would then group and factor to give you the two factors.
@NicholasAguirre-j4k
@NicholasAguirre-j4k 10 ай бұрын
In a similar vein, I did a similar process for FOILing (which I realize years later is actually a geometric method for showing it lol), where you draw yourself a "railroad" or "box" of the two factors and you multiply the terms in the little box by column and row, and add them up
@hardstuck6200
@hardstuck6200 10 ай бұрын
unfortunately the cross method doesn't work with all quadratics, which is why i find completing the square so much easier - it not only tells you the turning point of a quadratic, but also allows you to solve it and find both real and imaginary solutions - much like the quadratic formula.
@anujaamarasekara9513
@anujaamarasekara9513 10 ай бұрын
​​@@hardstuck6200The completing square method works on everything cause they aren't dependent on the discriminent while for factoring with the cross method requires the discriminent to be less than 0
@hardstuck6200
@hardstuck6200 10 ай бұрын
@@anujaamarasekara9513 i know thats what i said
@anujaamarasekara9513
@anujaamarasekara9513 10 ай бұрын
@@hardstuck6200 fair enough, my mistake
@helgefan8994
@helgefan8994 10 ай бұрын
In Germany we usually get taught a slightly different formula with only two variables p and q, after dividing the equation by 2 (in this case). x^2 + p x + q = 0 The 2 solutions then are: x = -p/2 +/- sqrt((p/2)^2 - q) EDIT (removing accidental strike-through): x = - p/2 +/- sqrt((p/2)^2 - q)
@silentguy123
@silentguy123 10 ай бұрын
I always find it weird seeing that much more complex formula compared to our "just divide by a first" approach 🤷‍♂
@helgefan8994
@helgefan8994 10 ай бұрын
@@silentguy123 The formatting messed up the formula, so that was probably a bit confusing. Actually I used that formula to work out both solutions in my head after just looking at the thumbnail. In my opinion it's a bit easier to remember than the a-b-c formula, but it may just be because that's what I was taught. Here are the steps I did in detail: 2 x^2 + x - 6 = 0 divide by 2 to get rid of the factor in front of x^2: x^2 + (1/2) x - 3 = 0 So p = 1/2 and q = -3. Now substitute p and q into the formula (from my original comment) to get x1 and x2 = - 1/2/2 +/- sqrt((1/4)^2 + 3) = - 1/4 +/- sqrt(1/16 + 3) = - 1/4 +/- sqrt(1/16 + 48/16) = - 1/4 +/- sqrt(49)/sqrt(16) = - 1/4 +/- 7/4 So x1 = - 1/4 + 7/4 = 6/4 = 3/2 and x2 = - 1/4 - 7/4 = - 8/4 = - 2 :-)
@ndwrestler
@ndwrestler 10 ай бұрын
I have zero use for any of this information. I'm almost 8 years into my career of treating people with pain which requires zero math. I still found myself watching this entire video and subbing. Something about it was just captivating. Maybe I'll be able to use this information when I'm helping my kids. Thanks!
@abominationdesolation8322
@abominationdesolation8322 9 ай бұрын
Eh? You don't deal with dosages, thresholds, and body weight proportions?
@ndwrestler
@ndwrestler 9 ай бұрын
@@abominationdesolation8322 Yes, but in a more nuanced way. I don't need to run equations or math to come up with things that I use. I utilize mostly a graded exposure approach and adjust it based on symptom/movement response. I know there's underlying math in there somewhere haha, but I don't have to actively do any of it in my head or on paper.
@jb_1971
@jb_1971 9 ай бұрын
It's good for the brain and you need your brain :P
@AndyJablonski
@AndyJablonski Ай бұрын
You explain things so well. Thank you. I’ve always been good at math but factoring never clicked for me. Now I understand it better. Thank you
@bprpmathbasics
@bprpmathbasics Ай бұрын
Thank you!
@SonOfZeusGaming
@SonOfZeusGaming 10 ай бұрын
We only learned the Quadratic formula in school, but I had a friend in that class that did Kumon and there they're also taught quadratic factoring. ofc if you learn the Formula you can do it all, and that's why the school only went with that, but damn factoring simple looking quadratics are so much faster tests become a lot easier. One of the few things from basic school that I kept hardcoded in my brain. I looked at this equation and took me 4 seconds to solve it. If you like Math (or is just quick calculator), I advise everyone to learn both ways cuz factoring speeds solving up so much you end up having way more time to solve the problematic (non factoring) ones.
@DimaMuskind
@DimaMuskind 10 ай бұрын
I just divided everything by 2 and got x^2 + 0,5x − 3 = 0 Then just usesd the Vieta, so x1 + x2 = −0,5 & x1 * x2 = −3 Here it is quite obvious that x1 = 1,5 & x2 = −2 or vice versa. One of the easiests quadratic equasions
@bidanfullko1
@bidanfullko1 10 ай бұрын
Ще один знаючий "святий Грааль" квадратних рівнянь)
@Dormazain
@Dormazain 10 ай бұрын
What was the deceiving thing about the formula? Is there something to trip over?
@godlyvex5543
@godlyvex5543 9 ай бұрын
I thought the answer is 1.5 and other people seem to think the answer is -2, so I probably hit the trap, whatever it is. But I don't see how 1.5 could be wrong.
@am_small
@am_small 5 ай бұрын
@@godlyvex5543 those are the two answers, they are both correct
@adamnevraumont4027
@adamnevraumont4027 10 ай бұрын
I sort of like throwing away the quadratic formula and always complete the square. So we aim for x^2 + 2 B x = C, here B=1/4 and C=3. Then we add B^2 to both sides. x^2 +2Bx +B^2 = C+B^2. The left is just (x+B)^2 (x+B)^2=C+B^2 (X+1/4)^2=3+1/16=49/16 Taking the square root: (X+1/4)= +/- sqrt(49/16) X+1/4= +/-7/4 X=3/2 or -2 (X-3/2)(X+2) we divided by 2 originally, so throw that in: (2X-3)(X+2) The quadratic formula is just a memorized version of that. But it isn't much faster than doing it by hand.
@itskarl7575
@itskarl7575 10 ай бұрын
I only ever knew to use the quadratic formula. It never occurred to me that you could also solve by factoring.
@miketheant1107
@miketheant1107 10 ай бұрын
Tbh looking at this here I'd say the quadratic formula would be easier and less likely to lead to mistakes, especially in real world scenarios.
@AcieAceSha45
@AcieAceSha45 Ай бұрын
What we usually do is use the ac method if there is a coefficient with x². Here's how: 1. Transpose the number 6 to make it 0. So it will become 2x² + x - 6 = 0 2. Multiply the a and c terms (hence the ac method). (2)(6) = 12 3. The equation would look something like this: x² + x - 12 = 0 4. Find terms that when you multiply it becomes -12, and the sum is 1 (or factor). 4 and -3 are factors: (4)(3) = 12, & 4 + (-3) = 1 5. Your equation should look like this: (x + 4)(x - 3) = 0 6. Do the Zero Product Property on getting the roots. x + 4 = 0 x = -4 x - 3 = 0 x = 3 7. Lastly, divide the roots with the previous coefficient of a, which is 2. x = -4/2 --> -2 x = 3/2 There's your answer! Feel free to use this method, I find it way easier, and our Math teacher says that this is a shortcut if ever you're given a limited time in class to answer.
@Algebrian_Guy
@Algebrian_Guy 10 ай бұрын
The method where you factored the thing is called "Middle term splitting" as I was taught. It is the same thing but instead focusing on the first and last term, we focus on the Middle term. In this example 2x^2 + x - 6, we first multiply the coeffecient of the first term and multiply it with the constant (2 and -6) to get -12. Then we have to find two coffecients of x so that when they are added, they give x as the sum, and also multiply to give -12 as product. In this case, they are (+3 and -4) and (-3 and +4). Then we split the middle term (x) in this way (2x^2 -3x +4x + 6) and then the equation is solved further, (2x^2 - 3x)(4x + 6) = 0, which will be solved to get both answers as you showed.
@malindemunich2883
@malindemunich2883 10 ай бұрын
But (2x^2 - 3x)(4x + 6) = 0 is not the same as (2x^2 - 3x + 4x + 6) = 0. The first results in 8x^3 - 12x^2 + 12x^2 - 18x = 0 => 8x^3 -18x = 0. This results in answers of x = 0, x = 3/2, x = -3/2.
@Algebrian_Guy
@Algebrian_Guy 10 ай бұрын
@@malindemunich2883 My mistake lol, it will actually be (2x^2 - 3x) + (4x + 6). It is a factoring trick that I was taught
@richfutrell753
@richfutrell753 10 ай бұрын
He forgot to factor out the x, but he remembered the jist of the method correctly
@malindemunich2883
@malindemunich2883 10 ай бұрын
@@richfutrell753 - Yeah, I wasn't trying to be hostile. I honestly hadn't seen that method before and was trying to see what would be the correct next step, so the idea is to eliminate the additional x from the original factor set? That seems reasonable. In other words, (just to clarify, because I am interested), his initial result of two factor sets would be correct excepting that you don't include the x on the second term of the first factor, not his correction of using the addition sign between them, yes? Because that seems to then create the correct solution.
@Algebrian_Guy
@Algebrian_Guy 10 ай бұрын
@@malindemunich2883 Even the greats make mistakes. I will look out for any mistakes in the future
@earth2k66
@earth2k66 10 ай бұрын
Bruh, I used to solve these in seconds when I was in grade 8, now that I have done masters in biology, this looks the hardest thing, when I can't remember how to solve it. 😭😭 Love the dose of nostalgia when listening to your detailed explanation of each step.
@0bm31770
@0bm31770 10 ай бұрын
I would have loved to have had you as my math teacher in college. I'm retired and don't need to do any math, but I enjoy your lessons.
@aaronh6169
@aaronh6169 10 ай бұрын
For some reason people hate completing the square but I find it easier than factoring. Standard form for reference: ax²+bx+c 2x²+x=6 First, make sure that your c (in this case 6) is on the right hand side. Then, divide everything by a In this case you have x²+0.5x=3 Then divide b/a (in this case 0.5) by 2, then square it You then have (0.25)² as a result Now add that on both sides x²+0.5x+(0.25)²=3+(0.25)² Notice that you have a polynomial on the left hand side that is a perfect square You can now condense it to (x+0.25)² So now you have (x+0.25)²=3+0.0625 Simplify to (x+0.25)²=3.0625 Then you take the square root So we have x+0.25=±√(3.0625) It would be easier to use fractions in this case because you can distribute the square root In any case then we have x+0.25=±1.75 So we have x=±1.75-0.25 Split this into x=1.75-0.25 and x=-1.75-0.25 And then you have x=1.5 and x=-2 Note that completing the square is the proof to the quadratic formula (Use the base equation ax²+bx+c and do the exact same steps as above) Anyways you probably have work on completing the square that I didn't find and I like your videos :)
@TheMasterGreen
@TheMasterGreen 10 ай бұрын
whenever I see videos where teachers try and explain fundamental concepts I always notice things that they could improve on so their explanation is clearer and easier to comprehend, however here I think everything you said and more importantly HOW you said it was perfection. Something I hope I can also do in the near future
@bprpmathbasics
@bprpmathbasics 10 ай бұрын
Thank you!
@benrosenthal4273
@benrosenthal4273 10 ай бұрын
​@@bprpmathbasicsI agree this was a great video, but one small thing I think could've been helpful is a short explanation of why you set to 0 in factoring to get answers.
@nerysghemor5781
@nerysghemor5781 8 ай бұрын
@@benrosenthal4273For me that’s where the graphical method comes in: I remembered all of a sudden that this is a parabola and what’s “0” is the value of y. The two solutions for x are where the parabola hits the x axis on each side on the way down. Also, other properties of the curve like how many inflection points or its shape drive the equation. I am very good at manipulating images and visually represented math/geometric concepts in my head…not as great with handling the nitty gritty number crunching, or dealing with garbage teachers throw out without them plotting out what’s going on visually first.
@steveeckman7578
@steveeckman7578 10 ай бұрын
Solve by completing the square! 2x^2+x=6 clear the leading coefficient: /2 x^2+1/2x=3 make a perfect square by adding half the middle term squared to both sides: + 1/16 x^2+1/2x+1/16=49/16 left side is now a perfect square as follows (x+1/4)^2=49/16 clear the ^2: square root x+1/4=±7/4 move the 1/4 x=-1/4±7/4 clean it up x=-2 or 3/2 Fun times!
@pon1
@pon1 10 ай бұрын
The quadratic formula is very interesting, you can analyse what happens in the square root with different values and it will reveal some amazing things :)
@bjornfeuerbacher5514
@bjornfeuerbacher5514 10 ай бұрын
What "amazing things" do you mean?
@Ribulose15diphosphat
@Ribulose15diphosphat 10 ай бұрын
@@bjornfeuerbacher5514 Positive: Two Reel Solution Zero: One Reel Solution Negative: Two Complex Solutions.
@bjornfeuerbacher5514
@bjornfeuerbacher5514 10 ай бұрын
@@Ribulose15diphosphat And what's amazing about that? That's standard, quite basic knowledge.
@dimwitted-fool
@dimwitted-fool 10 ай бұрын
@@bjornfeuerbacher5514might be amazing to someone who didn’t know it before. There was a time where you didn’t know it, and I bet you would’ve found it cool when you learned it. So unnecessarily condescending!
@bjornfeuerbacher5514
@bjornfeuerbacher5514 10 ай бұрын
@@dimwitted-fool Probably I misinterpreted him, I thought he meant that this would be amazing for BlackpenRedpen - and I think we agree that BlackpenRedpen has already known that for a long time. ;)
@tom-qj6uw
@tom-qj6uw 9 ай бұрын
When I was at school we used to (and had to, btw) actually calculate it instead of using the formula. So several decades later I tried to do so and could still do it: 2x² + x =6 | Divide by 2 x² + 1/2x = 3 | complete the square i.e. add 1/16 *explanation below x² + 1/2x +1/16 = 3 +1/16 | apply 1.binomial (x +1/4)² = 49/16 | extract root | x + 1/4 | = 7/4 x + 1/4 = 7/4 or x + 1/4 = -7/4 | -1/4 x = 6/4=3/2 or x = -7/4 -1/4 = -8/4 = -2 *completing the square: We want to reduce this equation using the first binomial formula, i.e. (a+b)² = a² + 2ab + b². We already made a equal x, so we only need to calculate b. With 2ab = 1/2x and a = x we get 2b = 1/2, so b = 1/4. Now we only need b² which is (1/4)² = 1/16. We add this to both sides of the equation and can consequently apply the first binomial formula
@LAK_770
@LAK_770 10 ай бұрын
I did it in my head successfully, it’s -2, but honestly I might not be able to solve it on paper if the mental math were harder. I’m getting stumped on what you can actually do to isolate the x cleanly
@NikkiTaLance
@NikkiTaLance 10 ай бұрын
I did in my head as well. The answer is 1.5
@8BitXatu
@8BitXatu 17 күн бұрын
I prefer to factor in parts for factoring quadratics with leading coefficient ≠ 1: 2x² + x = 6 2x² + x - 6 = 6 - 6 2x² + x - 6 = 0 2x² + 4x - 3x - 6 = 0 (2x² + 4x) + (-3x - 6) = 0 2x(x + 2) - 3(x + 2) = 0 (2x - 3)(x + 2) = 0 What I like about this method is that when you split x, it's more intuitive exactly what numbers should work. We need them to add to 1, and each of them to be a multiple or factor of either of the coefficients in the x² term or the constant term. I imagine this doesn't quite work cleanly for every problem, but this one seems to be set up for it.
@zionfultz8495
@zionfultz8495 10 ай бұрын
I am very happy with myself for finding the solutions in my head. First I tried +2, and got 8=6, so I saw that -2 would work by guessing. Then to get the other I used the quadratic formula (to a degree since I knew one solution I didn't need to do full version) and got 1.5
@Aracuss
@Aracuss 10 ай бұрын
Same, took me 10 seconds and I am not a genius ...
@godlyvex5543
@godlyvex5543 9 ай бұрын
I only found the 1.5 one, I never considered using negative numbers.
@zerg539
@zerg539 9 ай бұрын
I have been tutoring and teaching algebra for nearly twenty years and a random guy on KZbin teaches me a way to show how to figure out factor terms in a quadratic that is so much easier.
@dynaspinner64
@dynaspinner64 10 ай бұрын
Judging by the picture i thought this was supposed to be a trick question because if you flip the image upside down, it looks like e = x + e^xe 😅
@munteanucatalin9833
@munteanucatalin9833 10 ай бұрын
That one is also easy to solve
@dynaspinner64
@dynaspinner64 10 ай бұрын
@@munteanucatalin9833 I know about Euler's number and its value but idk if it has some special properties or something when it occurs in exponents. So I'm not sure how to solve it yet.
@munteanucatalin9833
@munteanucatalin9833 10 ай бұрын
@@dynaspinner64 That equation is a basic type of Omega function called Lambert W function. Just rewrite the equation using Lambert formula: 1=(e-x)e^(-xe) and make the appropriate substitutions then simplify it and solve for x as a normal exponential equation. Haven't you studied in college beta, Delta, gamma, sigma Omega functions? This is second term Math for a BA in Physics.
@dynaspinner64
@dynaspinner64 10 ай бұрын
@@munteanucatalin9833 I'm a 11th grade high school kid.
@munteanucatalin9833
@munteanucatalin9833 10 ай бұрын
@@dynaspinner64 O.ooo... Then keep studying. Math is a nightmare, but is useful and has a lot of practical applications.
@acetylsalicylicacid
@acetylsalicylicacid 6 ай бұрын
Here you don't have to resort to the quadratic equation. There is an interesting way to solve this that my teacher taught me a while ago. I'll write the steps below. Subtract 6 from both sides. 2x^2+x-6=0 Multiply the leading coefficient (2) with -6. x^2+x-12=0 Factor using the factors -3 and 4. (x-3)(x+4)=0 Divide the constants by the 2 that we originally multiplied them with. (x-1.5)(x+2)=0 Set each part equal to 0 and solve. x = 1.5 (3/2), x = -2
@TrimutiusToo
@TrimutiusToo 10 ай бұрын
That person from the post in the beginning probably forgot to subtract 6 on both sides... That would be the most common mistake anywa
@konggy97
@konggy97 9 ай бұрын
Even for someone who is already finished college, this is still a refreshing thing to remember. Stupidity is when you don't want to learn, not when you are unable to learn/solve a question
@Eluderatnight
@Eluderatnight 10 ай бұрын
I don't recall ever doing factoring and I got all the way through dif eq and calc3. I feel cheated.
@thenonsequitur
@thenonsequitur 10 ай бұрын
Calculus is way more useful than quadratic factorizations. I am 20 years removed from school and I still remember how to do calculus (including multivariable differential equations) and I still remember the quadratic formula but ask me to factor a quadratic now and I'm deer in headlights.
@kinyutaka
@kinyutaka 10 ай бұрын
I have no idea how they made it in the first place, but it blew my mind when I first worked the quadratic formula backwards. x = -b ± √(b² - 4ac) / 2a 2ax = -b ± √(b²-4ac) 2ax+b = √(b²-4ac) (2ax+b)²=b²-4ac 4a²x²+4abx+b²=b²-4ac 4a²x²+4abx+4ac=0 (4a)(ax²+bx+c)=0 ax²+bx+c=0 So, if you multiply the whole equation by 4a, and add the square of b in the right manner, then you can solve for x.
@whaaaaaaaaaaaaaaaaaaaaaaaaaaa
@whaaaaaaaaaaaaaaaaaaaaaaaaaaa 10 ай бұрын
Students can get so frustrated when they get to this level of algebra. They might be motivated to push through if they knew that this is basically the hardest thing to do in math until they get to differential equations. Get a solid understanding of advanced algebra and calculus is a breeze.
@Marinealver
@Marinealver 10 ай бұрын
Ah the completing the square ones were always caught me. But yeah quadratics are easy to solve. Since the constant is < 0 we know there will be 2 solutions just by graphing. First method is often factoring, if that doesn't work then completing the square. Lastly and finally is the quadratic equation.
@sheetalverma5829
@sheetalverma5829 10 ай бұрын
The method of middle term splitting is very common in india and we have vedic method of factoring all this is a class 7 maths in india
@sheetalverma5829
@sheetalverma5829 10 ай бұрын
India wale like kare
@DrupamHojaisa-xg8of
@DrupamHojaisa-xg8of 10 ай бұрын
Mujhe nahi pata tha ki middle term ko split karna vedic method hai😮
@sheetalverma5829
@sheetalverma5829 10 ай бұрын
Yes it is a vedic method
@harz632
@harz632 10 ай бұрын
X = 1.5 or -2 you can just do it in your head. If X = 1 then it's 3 If X = 2 then it's 10 so the answer is in-between those, X = 1.5 is 6 by approachment. Since it's to the power of a even number we need to check if there is a negative answer, X = - 1 = 3 and X = -2 is 6 so -2 is the other answer. When we put in 2 for X we could have guessed that the negative is also correct because the difference between the positive and negative number in the answer is always double the number put in to X (because you subtract X not add it since X is negative) so if X= 2 is 10 then by subtracting 2 times X you get the negative answer which is 6 X = 3 would be 21 so by my logic X = -3 should be 15 and calculating it we get 15 as the answer.
@Dangerousdaze
@Dangerousdaze 10 ай бұрын
I know you get this all the time but I really *do* wish you'd been my maths teacher in school!
@bprpmathbasics
@bprpmathbasics 10 ай бұрын
Thank you for your nice comment!
@thesimulator7
@thesimulator7 9 ай бұрын
I really appreciate that you showed how the first method of factoring can still work with coefficients on the x^2. Whenever I saw that in my math class I got so confused because my teachers never showed us how to factor with coefficients like that, they just immediately pointed to the quadratic formula.
@Austin_B626
@Austin_B626 10 ай бұрын
You could also do the method where you multiply a and c to get 12, see what mumbers add to +1 and multiply to 12 (-3 and 4) then substitute them jn for +1 to get 2x²+4x-3x-6. Split them apart (mentally) to get (2x²+4x)(3x-6) factor to get 2x(x+2)-3(x+2) to get the final answer (2x-3)(x+2). Then it's as simple as mental addition.
@donskiver
@donskiver 10 ай бұрын
I was never very good at factoring or completing the square...but I quickly memorized the quadratic formula and thats how I always solved quadratics in school.
@conlanger
@conlanger 10 ай бұрын
0:53 isn’t it equal to 0, not 6
@bprpmathbasics
@bprpmathbasics 10 ай бұрын
Ah yes! I said it wrong in the video but luckily I wrote it down correctly 😊
@TheSoup222222
@TheSoup222222 Ай бұрын
me, 20 years old, employed, no need for quadratic formula, haven't taken math classes in years, watching this video bc i love this guy's voice
@AmmoGus1
@AmmoGus1 10 ай бұрын
From the beginning just divide 2x²+x-6=0 by 2 to get x²+0.5x-3=0 Then figure out what numbers add to 0.5 and multiply to -3. 2 and -1.5 (X+2)(x-1.5)=0 X=-2 and x=1.5
@SuperNickid
@SuperNickid 10 ай бұрын
@AmmoGus1: You are also correct and you also prove that it does not work, the guy in the video also prove it does not work, with both his method, because the rules of algebra x must be equal to only one value, not 2 diffrent value,. Lets plug in your answer to found out if both answer work 2(x^2)+X=6 lets replace all X with -2= 2[(-2)^2]+2=6 2(4)+2=6 8+2=6, 10=6. That mean x=-2 is wrong. 2[(1.5)^2]+1.5=6 2(2.25)+1.5=6 4.5+1.5= 6 6=6 So the 1.5 actually work. It does not work because you found one incorrect answer and one correct answer. This is why it does not work. This is the solution replace X^2 to Y^2 so that way your formula as no problem because it would go like this Y=-2 X=1.5 and now solve it 2[(-2)^2]+1.5=6 2(4)+1.5=6 8+1.5=6 you see even this does not work. So no matter what it is always undertimine. If they is always more then one answer that work, or does not work, it is undertimine.
@bloroxcleach4098
@bloroxcleach4098 10 ай бұрын
​@@SuperNickidthat isn't true at all, the equation x⁴-5x²+4=0 has 4 solutions: 1, -1, 2, and -2. All of them work, you can try it yourself. X is not limited to one value. In fact, the way I came up with that equation was by multiplying 2 quadratics with that each have 2 solutions, x²-1=0 and x²-4=0. The first one's solutions are x={1, -1} and the second's solutions are x={2, -2}.
@robertnomok9750
@robertnomok9750 10 ай бұрын
@@SuperNickid Can you explain to me how exatly you managed to make x=-2 wrong? 2*-2^2+(-2)=6. 8-2=6.
@Cossieuk
@Cossieuk 10 ай бұрын
If you replace X with -2 it = 2[(-2)^2]-2=6 and not 2[(-2)^2]+2=6. There for 2(4)-2=6, 8-2=6, 6=6. In a quadrtic equation W will always have 2 answers and you can graph the equation and see the two points where the graph crosses the X axis@@SuperNickid
@thenonsequitur
@thenonsequitur 10 ай бұрын
@@SuperNickid You substituted wrong in the x=-2 case. You wrote "2[(-2)^2]+2=6". You correctly substituted x with "-2" on the first term but you incorrectly substituted x with "+2" on the second term. You should have written "2[(-2)^2]-2=6", which simplifies to "6=6" and checks out.
@kchez110
@kchez110 8 ай бұрын
So much fun! Just discovered this channel. I’ve always loved math. Now in my 60s, Ph.D. chemist.
@bprpmathbasics
@bprpmathbasics 8 ай бұрын
Thank you!!
@annanay007
@annanay007 10 ай бұрын
2x²+x=6 2x²+x-6=0 2x²+4x-3x-6=0 [middle term split] 2x(x+2)-3(x+2)=0 (2x-3)(x+2)=0 So either of the two must be zero because their product has to be zero if 2x-3=0, x=3/2 if x+2=0, x=-2 Easy peasy
@annanay007
@annanay007 10 ай бұрын
If you want to know how middle term split works, here I am eqn form is ax²+bx+c=0 Find a*c Here a=2 and b=6 ac=12 Now prime factors of 12 are the lowest value prime numbers you need to multiply to get 12 12=2*2*3 Now make two sets that on addition or subtraction give 'b' If the last value is negative you need to do subtraction and if positive addition Here the two sets can be 4x-3x Now take something common from two parts of the eqn and solve it Using the same, solve Easy: x² + 2x + 1 = 0 Hard: x² + 2x - 3 = 0
@himalayavalvi4651
@himalayavalvi4651 10 ай бұрын
Equation is (+c), so how come (-6) is utilised
@aeojoe
@aeojoe 10 ай бұрын
Both are easy
@annanay007
@annanay007 10 ай бұрын
@@himalayavalvi4651 value of c is -6 So bx+(-6) bx-6
@annanay007
@annanay007 10 ай бұрын
@@aeojoe clickbait it is 😉
@martineriksson03
@martineriksson03 10 ай бұрын
we weren’t allowed to use the quadratic formula (or PQ-formel in Swedish, as it is a simplified version of the regular one) in our first uni math course for some reason I can’t remember, instead they wanted us to finish the square* even though they both yield the same result. I think the reasoning behind the rule is because the quadratic formula comes from finishing the squares *if you do not know what finishing the square is, I’ll try my best to explain it below: suppose you have ax^2+bx+c=0. then you factor out a so you get a(x^2+(b/a)x+c/a) = 0. then you look at the coefficient for x. when expanding a binomial (α+β)^2 you get (α)^2 + 2αβ + β^2, so to ”reverse” operation that you would take the α square and the 2αβ and divide both by α, and the remainder of 2αβ by 2 since the expansion is αβ + αβ. that would leave you with (α+β)^2. doing the same ”reverse” with the original question i posted, you would ”divide” the x squared part and the (b/a)x part with x, and also divide b/a with 2, leaving you with a((x+b/(2a))^2)+c/a)=0. the thing is though, we can’t say the equations are equivalent with one another since expanding the square in the second form would produce an extra +(b/(2a))^2, so in order to have equivalency we must subtract this outside the brackets, so we end up with a((x+b/(2a))^2-(b/(2a))^2+c/a) = 0. from this point you often remove the a for simpler calculations (but remember to put it back in the end) and you move forwards with putting the terms outside the squared brackets on the right side, so we would get (x+b/(2a))^2 = (b/(2a))^2 - c/a squarerooting both sides gives x+b/(2a) = +-sqrt((b/(2a))^2-c/a) x = -b/(2a) +- sqrt((b/(2a))^2-c/a) from this you can factor out 2a as a denominator for both terms in the right side, and to factor in c/a we find so sqrt(c/a) = sqrt(H)/2a => c/a = H/4a^2 (c/a)*4a^2 = H = 4ac. Finally, putting all this together we get the final expression of X = (-b+-sqrt(b^2-4ac))/2a, which is the quadratic formula
@martineriksson03
@martineriksson03 10 ай бұрын
anyways, the point is that because of this rule i’ve grown fond to use this method instead even if it is longer and if we’re allowed to use quadratic formula during exams
@NadiehFan
@NadiehFan 10 ай бұрын
@@martineriksson03 The derivation you give of the ABC Formula (as it is known in Sweden and some other countries, but not in English speaking countries) relies on _completing the square_ as it is known in English. In my language this is known as _splitting off the square_ which is not quite the same but the two terms are mostly used interchangeably. While solving quadratic equations by completing the square or to derive the ABC Formula you can avoid the use of fractions until the very end using what is currently known as Sridhara's method but which was referred to in high school algebra books throughout the 19th century as the Hindoo method. This is by far the easiest method to derive and prove the quadratic formula but can be somewhat less practical in solving actual quadratic equations by completing the square because the coefficients tend to become large. Let's start from ax² + bx + c = 0 where a, b, c are assumed to be real numbers and a is not zero, otherwise we would not have a quadratic equation. First subtract c from both sides which gives ax² + bx = −c Now multiply both sides by 4a to get 4a²x² + 4abx = −4ac or (2ax)² + 2·(2ax)·b = −4ac Add b² to both sides to make the left hand side a perfect square and we have (2ax)² + 2·(2ax)·b + b² = b² − 4ac which can be written as (2ax + b)² = b² − 4ac Assuming b² − 4ac is not negative this gives 2ax + b = ±√(b² − 4ac) Subtract b from both sides and then divide both sides by 2a to get x = (−b ± √(b² − 4ac))/2a and we are done. This method is attributed to Śrīdhara also known as Śrīdharācāryya or Śrīdhara Acharya but commonly spelled Sridhara in English sources. Sridhara was an Indian mathematician who lived in the latter part of the 9th and the early part of the 10th century. His original text where he discusses his method appears to be lost, and we only know about his rule from a quotation in the works of a later Indian mathematician, Bhāskara II, who lived from 1114 to 1185. In India the quadratic formula is known as the Śrīdharācāryya formula and in Brazil the quadratic formula is known as Bhaskara's formula. In parts of Germany and Austria it is known as the Mitternachtsformel (midnight formula) because, as the story goes, students were required to remember it by heart even if they were woken up in the middle of the night.
@kafkatotheworld
@kafkatotheworld 10 ай бұрын
finally my practice blessed me, as soon as I saw the problem I figured it out I feel good especially because I always got bad grades in my tests I feel confident Sorry for bad english it's because I don't respect the language btw a random help, if you can please I am a high schooler, I especially like math can understand concepts and am having fun with it though still I get bad grades any suggestions
@cacalightx
@cacalightx 10 ай бұрын
Well, it really depends on how much you practice. Understanding concepts and solving questions are two different things. You could understand the concept, but not understand the question. Sometimes, they twist the question to make it harder for you to understand. Or... you take a lot of time to solve simple questions. That again, can be solved by practicing questions by limiting yourself to a certain time period.
@kafkatotheworld
@kafkatotheworld 10 ай бұрын
​@@cacalightx that's the fun part I don't know; I practice hard, I do everything I can possibly do but still the same low result And the main thing it's always the exams or tests that I cannot do math, whenever I see those questions on the exam(same difficulty) I cannot, I also try to do those same problems given in exam/tests at my home, and guess what I can do them easily I don't know what's the problem with me Sorry if it's a bit confusing, English is not my native language so I couldn't explain properly
@saythealphabet776
@saythealphabet776 10 ай бұрын
​@@kafkatotheworldcould be your teacher's fault. Some teachers are horrible at explaining things. Pay all the attention you can in class,do all your homework and you should be golden, but there's not much more you can do if your teacher sucks. Ask questions if you don't understand something.
@darklightmotion5534
@darklightmotion5534 10 ай бұрын
​@@kafkatotheworld maybe its psychological and the exam environment hinders you in some way. Are you too stressed? Are you too anxious? Does it distract you? Take a deep breath and ground yourself.
@peterpumpkineater6928
@peterpumpkineater6928 10 ай бұрын
Bro who practices math
@lazydadsgarage
@lazydadsgarage 8 ай бұрын
I love that you did a simple problem that's still tricky to those of us that have been in some advanced math for a while
@Salamat__
@Salamat__ 10 ай бұрын
My brain at first sight : -2
@JTCF
@JTCF 10 ай бұрын
I am proud of myself. Wrote down the problem from the thumbnail and solved it before going into the video.
@ravirajchilka
@ravirajchilka 10 ай бұрын
I studied in my school but still dont know where these equations are used. I think its important to study why need to learn it rather than solving equations. After 12 years I realized the importance of calculus. In my school I was just solving it for exams
9 ай бұрын
I solved it by immediately seeing -2 as a solution, then finding the minimum of the parabola by factoring out (a^2 + 2ab + b^2) from the formula. Found it at -1/4 and mirrored -2 on it to receive 1.5.
@farofflegend7113
@farofflegend7113 10 ай бұрын
Why doesn't taking the variable common in a quadratic equation gives the answer. For example the equation : 2x^2+x=6 Taking x as a common factor and writing it as x(2x+1)=6 Then, x = 6 or 5/2 which isn't the correct answer. Why?
@carultch
@carultch 10 ай бұрын
Good question. The reason this doesn't work, is that after you got to this step: x*(2*x + 1) = 6 You can't assume what either of the two factors should equal, when solving for x, the same way you could assume either factor equals zero, when their product equals zero. For an equation such as x*(2*x + 1) = 0, you know this is only possible if either of the two factors, or both of the two factors equal zero. At least one factor must equal zero, in order to annihilate the entire left hand side to zero. This is because it is impossible for any finite quantity of non-zero numbers to multiply to zero. If x = 6 is a solution you can infer from the first factor, this can only be possible if (2*x + 1) is equal to 1. You can narrow it down to a finite list of possibilities for each factor to equal, and use that to reason your way to solve it. But, it's much better to learn how to solve a quadratic more directly, instead of by trial and error. Or at least, to take better educated guesses to solve them. Here's how I'd make that method work: x*(2*x + 1) = 6 Candidates for what each factor equals: x = 1, (2*x + 1) = 6 x = 2, (2*x + 1) = 3 x = 3, (2*x + 1) = 2 x = 6, (2*x + 1) = 1 Because of the leading coefficient of 2, we also have fractional candidates: x = 1/2, (2*x + 1) = 12 x = 3/2, (2*x + 1) = 4 We also have to duplicate this for the negative versions of these candidates. This means we will have only two hits, and ten misses. This might work well when your c-term is a prime number, and you have a shorter list to investigate, but a composite number with lots of factors will add up to a lot of work quickly. The candidates that are hits, are: x = -2, (2*x + 1) = -3 x = 3/2, (2*x + 1) = 4
@harshkharwar5951
@harshkharwar5951 10 ай бұрын
U can use Shredharacharya Formula to solve this x=-b +- √b²-4ac upon 2a ... We did these type of questions in class 4
@black_m1n825
@black_m1n825 10 ай бұрын
When I was introduced to factoring at school, that became my favorite way of solving these equations.
@DrEnzyme
@DrEnzyme 9 ай бұрын
The proof of the quadratic formula is one of the most beautiful things my (limited) mathematical ability can comprehend. There's a bit where you seemingly add a random term to both sides (b/2a)^2 and it all comes cascading down into the final result. It's very satisfying.
@kingpet
@kingpet 10 ай бұрын
Quadratic equation is like the bread and butter of algebraic equations in my middle school math class.
@darrenwatters3511
@darrenwatters3511 9 ай бұрын
I did it in my mind in all of 30 seconds max... it's really easy to simplify this problem in one's mind.
@Gr3nadgr3gory
@Gr3nadgr3gory 10 ай бұрын
Aftear learning math most of the time i can look at an equaion and guess how long it woudl take me to solve. Its either 5 seconds or 30 minutes or more.
@battleclover9537
@battleclover9537 10 ай бұрын
I’m grateful that I haven’t had to use this for anything in my life outside of a math class
@jeffreyfoster8413
@jeffreyfoster8413 10 ай бұрын
You glossed over it as a given but it should be noted that -1^2 does not equal (-1)^2.
@nerrickk9024
@nerrickk9024 9 ай бұрын
The quadratic formula lives rent free in my head thanks to my teacher. To the tune of "pop goes the weasel": X equals the opposite of b, plus or minus square root, b squared minus 4 a c, all over 2 a!
@AzureKyle
@AzureKyle 10 ай бұрын
What I ended up doing was similar to the first method, though I never knew of the tic tac toe method, that's actually pretty neat. Basically, like in the video, I subtracted 6 from both sides, but then I divided by 2, resulting in x^2+0.5x-3=0. Then I factored it out, which was the most difficult part for me, since I made the mistake of dividing it first, but I ended up with (x+2)(x-1.5), which then told me the answer was both x=-2 and x=1.5, or 3/2 as he puts it in the video.
@eavening4149
@eavening4149 8 ай бұрын
I never knew about such a clear and straightforward method for factoring when I was learning this. This tic tac toe method would have been amazing!
@Oliver_DaNinja
@Oliver_DaNinja 9 ай бұрын
Going through school and actually learning how to do these problems that are considered tricky without needing the explanation is the biggest flex (I’ll never use this again).
@aqwkingchampion13
@aqwkingchampion13 9 ай бұрын
I never memorized the quadratic formula, and I never liked cross-checking when factoring, so I did it the hard way: Completing the square. 2x^2 + x = 6 x^2 + (1/2)x = 3 x^2 + (1/2)x + 1/16 = 3 + (1/16) x^2 + (1/2)x + 1/16 = 48/16 + 1/16 x^2 + (1/2)x + 1/16 = 49/16 (x+1/4)^2 = 49/16 x+1/4 = +/-(sqrt(49/16)) x+1/4 = +/- 7/4 x= +/- (7/4) -1/4 x= (-1 +/- 7)/4 x= -8/4 | 6/4 x= -2 | 3/2
@hamakakun
@hamakakun 10 ай бұрын
If only this channel exist during my school years. I cant digest this during that time, but looking at this now it make sense. 😢
@bvssmouq6gamingofficialyt
@bvssmouq6gamingofficialyt 10 ай бұрын
Fast method: multiply A times C. Find the factors of that number that would add up to your b value (in this case 2×-6=-12 so youd factor -12 into -3 and 4 which -3+4=1) from there you would divide them by the a vaule if they can ans then put it into factored/intercept form. (In this case it is (x+2)(2x-3)), then set one of them = to 0 an solve for x. Then do the same for the other. (X+2=0 x=-2, 2X-3=0 x=3/2) This method WILL ALWAYS work IF the factors can add up to the B value. If not, use this or quadratic formula (i'd use the formula).
@toast99bubbles
@toast99bubbles 10 ай бұрын
I hate it when people put things like this question, where the solution is easy to me, but they ask if they're stupid for not getting it. Like it seems as though people have led them to believe that just because they don't see what is obvious to me, they must be stupid, but that's not the case at all. Thanks for doing this for the person who posted the question because people who make these posts need to know that they aren't stupid at all, there's likely an easy way to solve it that they just haven't spotted yet and it's not their fault that they haven't spotted it.
@guyonYTube
@guyonYTube 10 ай бұрын
Generally, when factorising quadratics I try to do a small trick. Most would already know that you need to multiply the coefficient of x^2 and the constant(product could be negative), and then try to get two multiple(could be negative) that when added/subtracted will give the coefficient of x(again, could be negative). Well, sometimes you'll have to try a lot of factors, but to reduce that, I use my trick, with prerequisite that the coefficient of x^2 is positive; if it isn't, just mutiply by -1): If the constant is positive, then the sum of chosen factors should be the x coefficient. Now, if the coefficent of x is negative, just use the negative versions of the factors. If the constant is negative, then the difference of chosen factors should be the x coefficient. Now, if the coefficient of x is negative, use the bigger factor as negative and the other positive, and if it is positive, use the bigger factor as positive and the other negative. After this, finding the correct factors might become hard for harder equations. I'll put my thought process for this if it might help. Example:- 6x^2 +17x +12 = 0 6*12 = 72 Since the product is positive, sum of factors should be 17. Now for the thought process, I'd first look at 6 and 12 themselves. Product can be rewritten as (2*3) * (2*2*3) 6+12 = 18 > 17, so I'd want to increase the smaller factor and decrease the bigger factor. I'll switch around 3(from the bigger number, 12) and 2(from the smaller number, 6). (3*3) * (2*2*2) = 9*8 9+8 = 17, as needed Therefore, write the equation as follows: 6x^2 +9x +8x +12 = 0 3x(2x +3) +4(2x +3) = 0 (3x +4)(2x +3) = 0 Another example:- 2x^2 +3x -90 = 0 2*-90 = -180 Since the product is negative, difference of factors should be 3. Now for the thought process, difference between 2 and 90 is obviously too big, so I can rewrite it. - (2*3*3*5) * 2 - (2*2*3*3*5) - (2*2*3) * (3*5) - 12 * 15 Difference between 12 and 15 is 3, so this will work. Therefore, write the equation as follows: 2x^2 +15x -12x -90 = 0 x(2x +15) -6(2x +15) = 0 (x -6)(2x +15) = 0 When the x^2 coefficient is 1, the process becomes simpler. Example:- x^2 +18x +32 = 0 Since 32 is positive, sum of factors should be 18. 32 is 2*2*2*2*2 (2*2*2) * (2*2) 8*4 8+4 = 12 which is too small, so we have to increase the bigger factor and decrease the smaller factor. (2*2*2*2) * 2 16*2 16+2 = 18, done Now the final part can be done faster if the x^2 coefficient is 1. 18 is _16+2, so the equation becomes: (x+16)(x+2) = 0
@kirkanos771
@kirkanos771 10 ай бұрын
the negative sign after "Example:" has been very confusing.
@my_1buddy
@my_1buddy 9 ай бұрын
I am actually surprised. I usually believe that because I don’t understand something from the beginning, I really am dumb. I always had trouble to this day with factoring, but somehow seeing the tic-tac-toe method changed things. I just could not visualize or write it down on paper before, but now I can clearly work it out in my head properly. Thanks, bprp bro.
@rako7169
@rako7169 10 ай бұрын
just multiply the coefficient of x² and the constant. factor out the product of those two such that you get two factors which account for the middle x term of the equation. when this doesn't work, i use the quadratic formula
@T0NI_
@T0NI_ 10 ай бұрын
Can't believe it's "only" been like 4 years since I last used the quadratic formula, and I already forgot half the process lol. This was a fun reminder
@Llanchlo
@Llanchlo 3 күн бұрын
WTF? This popped up randomly in my timeline. I have not factored a quadratic since I sat my Maths A level 50 years ago. I solved this in my head in about 30 seconds. I knew I had to take the 6 over. Once done it looked obvious that it would factorise simply since 2x3 = 6 and 6 - (2+3) = 1. So my two brackets needed to be (2x +/- (2 or3)) and (x +/- (3or 2). I could not remember that grid algorithm, although i guess I was taught it, but since I did remember that 4-3=1 which was the co-efficient of x it tokk only a few seconds to work out which combo worked. It actually took me longer to double check the positive solution as I could not remember what 1.5 squared was .... and it didn't occur to me to treat it as 3/2. So there must be some rust in the grey matter after all.
@richardbradley1532
@richardbradley1532 10 ай бұрын
I learned the formula 50 years ago and it is stuck in my head to this day! 😂
@thomaskim5008
@thomaskim5008 10 ай бұрын
Another method is check for the rational solutions and using the synthetic division
@zelandakhniteblade5436
@zelandakhniteblade5436 9 ай бұрын
Simpler method for those who have difficulty going directly from the quadratic to the factors. For ax^2 + bx + c = 0, calculate a*c, here 2 * -6 = -12. Now look for 2 numbers that multiply together to give this number and add together to give b. Those numbers here are 4 and -3. Now replace b with these 2 numbers: 2x^2 + 4x - 3x - 6 = 0. Now group terms 1 and 2, and terms 3 and 4, so that they have a common factor: 2x(x+2) - 3(x+2) = 0. Combining: (2x - 3)(x + 2) = 0. It is a little longer than the methods most schools teach but it each step is simple meaning that you will never go wrong, whereas I see errors in the direct factorisation all the time. Any school pupils who have trouble with this process, please try this!
@acticlacid
@acticlacid 10 ай бұрын
I haven’t seen that chart method for cross multiplication before, but it feels like a good way to keep it organized and reduce the amount of mental math necessary
@runswithsoda
@runswithsoda 9 ай бұрын
Here I am reviewing this stuff late at night because I forgot all of this. Gotta keep my brain sharp! I really appreciate your clear explanations.
@the_arizona_ranger0213
@the_arizona_ranger0213 9 ай бұрын
I forgot how much I enjoyed my math classes. This gives me such a blast from the past.
@valdelta8096
@valdelta8096 10 ай бұрын
To factorise, I've always been taught that- ax²+bx+c Separate bx into such a manner that the product of their multiplication is equal to ac and the sum of them equals to b. So 2x²+x-6 would be 2x²+4x-3x-6 2x(x+2) -3(x+2) (x+2)(2x-3)
@domagojoinky8262
@domagojoinky8262 10 ай бұрын
Get that six to the left side so you get zero on the right so you get a x squared + bx + c equals zero shape. Then, use the formula for quadratic equation and problem solved.
@TheOriginalFayari
@TheOriginalFayari Ай бұрын
The quadratic formula is burned into my skull. (-b + or - sqrt (b^2 ‐4ac))/2a by that Don't Stay In School song.
@CLNCJD94
@CLNCJD94 10 ай бұрын
I’ve started watching your videos to kinda test myself on math equations I used to know how to do. It feels good that I can keep up and still learn/relearn these lessons. Thank you.
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