3 to (x/2) = 12, many don’t know where to start

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[@Johnny38249]

He's one of the best math teachers I've encountered in my lifetime, and I've been around! He seems willing to work with his students and encourage them to study this fabulous science!

[@vwr32jeep]

He could be if he shortened the solutions. A 20 min video is not helpful. Every video contains way too much backstory, smiley faces, and sales pitch for the importance of math. It would be much more helpful to have links to previous videos explaining order of operations or methods needed to solve it… instead of a “brief” explanation EACH TIME. I do like the vids, but it’s frustrating to have to keep hitting the fast forward so many times.

[@juannieto1987]

Your videos are outstanding they were what made me try out your math program. You are direct and to the point. The enthusiasm and positivity you bring is priceless.

[@topkatz58]

You can solve using logarithms. But by the process of elimination is faster. 3² = 9 3³ = 27 Therefore 2 < x ÷ 2 < 3 If x = 8 yields 4 too big Same with 24 If x = 2.26 yields 1.13 too small So answer is d) 4.52

[@BrandurDavidsen-wd2lp]

x/2 x log 3 = log 12 x/2 = log 12/ log 3 x = 2 x log 12/ log 3 x = 4,52

[@francisdelpuech6415]

That’s what I did. Obvious

[@joseeoliviero6078]

Seems easier to start by raising both sides by the power of 2. Then by the power rules, you have 3^x=144. That is how I started the problem. Then do your log functions.

[@johntynio3416]

I should be able to solve it easily! Come on, if I could do that would I be watching at all? John, you are great at math for sure , that's why I watch! But I don't need comments that try and make me feel dumb for not thinking something's easy! Thanks John!

[@johnhudelson2652]

I did not need a calculater or a log table: So here's my logic of getting my choice of d: 3^2 = 9, so for 3^y = 12, y would be slightly larger than 2. And x/2 woulc be slighlt larger than 2. So the multiple choice answer is d.

[@russelllomando8460]

got it. logic dictates the exponent has to be a little more than 2 as 3 sqrd = 9 & 3 cubed = 27) 4.52 - 2 = 2.52 as the exponent. thanks for the fun.

[@the318pop]

It's x÷2 not x-2

[@russelllomando8460]

thanks for the catch@@the318pop

[@HR-wd6cw]

If you use deductive reasoning, you can get rid of 2 of the 4 solutions, as they don't make sense (for example 3 to the 4th power is 81, and so x cannot be 8 -- must be less than 8, so that also rules out 24). However we do know that 3 to the 2nd power is 9 and that 3 to the third power is 27 so it's somewhere in between. Actually you don't really need to do much math except figure out what 3 to the 2nd power and the 3rd power is to narrow down the answer. But technically you can do this in your head too (not even need logs; of course using logs is the mathematically correct way to solve this, but if you didn't know, you could use trial-and-error here too with some reasoning). (Actually you can eliminate answer C pretty quickly too if you figure that 2.26 / 2 is 1.13, which is less than 2 and we know that 3 squared is 9, which is still too low, but 4.52 / 2 = 2.26, and that might work because it's more than 2, but less than 3.

[@phrankus2009]

Trickier than it looks ... First: The exponent is, both, confusing and distracting. * Given: In terms of MDAS Ops, The "x÷2" is ALL depicted as *superscipt but, for the sake of clarity, I would recommend enclosure, within parenthesis (however redundant). ... ** Let us disregard the "factored form", of the exponent "(x÷2)" and substitute with "(?)". ENGLISH: How many times to multiply 3, by itself, to attain 12 ? .. ** Intuitively, 3*3=9 and 3*3*3=27 and 12 is much closer to 3 squared so, looking at the given answers, we know that we are looking for an answer that is twice "(?)" or (BETWEEN 4 and 5) TOOK ME LONGER THAN I HAD HOPED

[@devonwilson5776]

Greetings. The answer is d, 4.52. The expression 3^X/2=12 boils down to 3^X=12^2. That is X log3=log 144, and X =log 144/log 3=2.158362492÷ .477121254= 4.523719014= 4.52 approximately. Lovely. 3^X/2=12 can be written as 3^(X/2×2/X)= 12^2/X to get rid of the exponent X/2. Now we have 3=12^2/X. Moving forward we want to get rid of the root X. We will accomplish this by raising all the terms of the expression by X to get 3^X=12^(2/X ×X/1). That is 3^X=12^2. From here you will employ logarithmic functions. Try it and see.

[@denzilgounden4044]

I use this method it much easier

[@nancyholcombe8030]

Got d) by guesswork but appreciated the math lesson afterwards! Not all equations are so simple to guess! 😊

[@jkotsche7035]

how about squaring both sides 3^(x/2)^2 = 12^2 3^x = 144 x log 3 = log 144 x = (log3+log3+log4+log4)/log3 x= (2+2log4)/log3 => 2(1+log4)/log3 where log4/log3 is log4 base3

[@michaeledwards2251]

I started by observing 3 power 2 is 9. 12/9 is 4/3. Square root 3 is about 1.7, 4th root about 1.3. So 3 power x/2 =12 gives x/2 approximately 2.25. X is double, approximately 4.5. Viewing the options, (d). Giving this a multiple choice, and has to be solved in 10 seconds, no one will have time for anymore calculation.

[@pinkalex7703]

I agree too ... he's a very great teacher and professor...😊😊😊 How great he is😮😮😮😮

[@Astrobrant2]

Wouldn't it be easier to just do: x/2 (log3) = log12 x/2 = log12/log3 x/2 = 2.26 x = 2.26 times 2 = 4.52 ?

[@melvinthomas6349]

Too much time wasted in solving problem.

[@jillmondt5398]

Dude, I am confused more from this rhan before. Please redo this teaching how to do this WITHOUT a calculator and the "log" talk.

[@tikaanipippin]

just by guessing 3^2=9, and 3^3=27, then3^x is between those two choices , so x/2 must be between 2 and 3 - the multiple choice of between >4 but

[@terry_willis]

What is 1 + 1? (Hint - It's 2). He could make a 20 video explaining this and have the student so confused that the student drops the math class and switches to Art 101 or phys ed.

[@tomtke7351]

where did your confusion begin?

[@tomtke7351]

nothing wrong with Art 101 or with phys ed...

[@dazartingstall6680]

So which are you; Russell or Whitehead?

[@rjones6219]

I agree, helluva lot of waffle.

[@tomtke7351]

@@rjones6219 what waffle??

[@larrywiener6327]

It has to b D because if you subsitute A B or C for x they are either tt large or too small

[@yiutungwong315]

D.4.52 It's Also Guess 3^2 = 9 3^3 =27 So 3^2.26 = 12 2.26 × 2 = 4.52

[@Em-wb4kf]

I see that if 3 to the x power is equal to 2 times 12, therefore 24, then x has to be 8. (3, 8 times makes 24, then divide that by 2)). What do you think?? Makes sense to me. I choose a) 8.

[@user-ri6rn7ti5h]

So do I

[@Em-wb4kf]

I think I got it wrong because I misunderstood how to work out te exponent 'x'. It isn't 3 times 8. It is 3times 3, then that answer, 9, times 3, and so on 8 times. @@user-ri6rn7ti5h

[@johnplong3644]

Some times. 10:07 you don’t have to actually do the Algebra In particular this problem Will know the answer is in front of us Choice a And b see way off so you are left with c and d with out doing a lot of math in my head I came up with D I had a teacher who gave up a multiple choice test He told us there were a lot of problems He said you definitely won’t finish any many of your are going to not do well and many will fail Your goal is to get as many right He said you are going to come up with different strategies to pass this test We were just given the test with out any notice or preparation The one hint or help he gave us The correct answer in is in front of you use that A lot of the problems you solve in you head pretty quickly Pretty much you had to eliminate the wrong answers I did well on it Some of the problems were extremely difficult I didn’t attempt to do them I went to the next problem This basic strategy was do what you know and if there is time go back In some problems later in the test you were given the correct answer It was a very valuable lesson to learn He gave a similar test a few days later most did well on it lesson learned

[@anantamurthy5525]

3^x =144. 144>3^4 but less than 3^5 Ans is between 4 and 5 4 .52

[@jerrypaquette5470]

3 ^2 = 9, 3^3 = 27 Therefore X/2 has to be larger than 2, but less than 3. 4.52 is the only logical answer.

[@Astrobrant2]

You don't need to check c with a calculator. 2.26 divided by 2 is 1 point something, clearly not enough to make 12. Or, x/2 has to be more than 2, because 3^2=9, which is less than 12. So x has to be more than 4.

[@cherylhill3302]

I love him. I just think he puts too much unnecessary language in the video, then needed. We just want him to get to the point!

[@RustyWalker]

Well 3^2 is 9 and 3^3 is 27 so x/2 has to be a smidge over 2 meaning x must be a bigger idhe over 4, so D. Now, to work it out properly.

[@TomTom-yw4pm]

₃ˣ÷² ₌ ₁₂ Squaring both sides; (aᵇ)ᶜ= aᵇᶜ hence ₃(x ÷ 2)² =₃(x/2) *2 ₃ˣ ₌ ₁₂² xlog₃ 3= log₃ 144 x= log₃144 x=4.52

[@rodfulford4306]

What is the question? If we are finding x, then answer is D . No real calculation needed as x/2 must be between 2 and 3

[@SuperVt100]

Are logs really old? They were first publicized in 1614 by John Napier. A logarithm is the inverse function of exponentiation.

[@stinkbug4321]

Yes, I have a long in my backyard that is hundreds of years old.

[@DuyenNguyen-cx7do]

3exp2= 9, 3exp3= 27. Therefore x/2 must be between 2 and 3 or x must be between 4 and 6. Only answer d satisfied, x≈ 4.52.

[@usa40111]

D. 4.52

[@stevenjohnson1143]

D dividing it by 2 gives c

[@tigerhorn2954]

How do you solve this without a calculator?

[@tonydolosa759]

4.52

[@stevenjohnson1143]

The way I solved it realizing the first two are wrong and gave me 2 real choices left and knowing I am dividing x by 2 the quociant will be between 2 and 3 eliminates c leaving d as the correct answer

[@pamelabyars3983]

D) 4.42

[@marknieuweboer8099]

3² = 9. 3³ = 27. So x:2 = 2, something. So x = 4, something. D.

[@user-ht9js1kz6r]

This question is pretty easy. 8 is much bigger.24 is even bigger. 2.26 is too small. Then the answer is d

[@Cariboolife]

C) 2.26, opps read the equation wrong. X/2 not 3x/2. So D) 4.52

[@nyneeveanya8861]

Guesstamated. So 3 squared is 9 and 3 cubed is 27 so closest answer to 12 must be over the square and a lot less than the cube and that is 4.52.

[@Mike80097]

D by inspection

[@Ed19601]

None of the answers is correct. Answer d) is the closest (it comes to 11.97) but with that it is just as incorrect as the others. But if that isca close enough outcome, it is easily solved: 3^2=9, which is too small, 3^3=27 which is to big, so x+2 is in between 2 and 3, so x is in between 4 and 5. Only reply possible then is d. It is not rocketscience

[@SUJAMUK]

8?

[@ALEXANDERJMORGAN]

D

[@jimwalshonline9346]

Just looking at it, I'd eliminate a and b, and pick d...

[@maxkennedy5073]

x/2 must be bigger than 2 and less than 3 thus it must be 4.52/2.

[@petergomes8788]

d..

[@sriindrawati7572]

D. X =4,52

[@hasushah5290]

8

[@patriciagrubb1616]

My answer is A. 8

[@mariaeye1]

24

[@1961ebutuoy]

x = 50.3017

[@aryusure1943]

Common sense, logic and a calculator. You can't miss. Now let's see the proper method. I don't want to lose my newly found algebra "skills". ;)

[@davidwatson7604]

Got a happy face but had almost zero confidence. Algo boost!

[@normalucia9930]

Was hoping to learn without the use of calculator 🤦🏻‍♀️

[@joseortalizsr8384]

something divided by 2 is 12. so that would be 24? my guess is d!

[@edjo487]

11.975? I love your videos, but that is not 12 in my world. Rounding up? So, pick the best answer? lol

[@boraorhan8398]

10 seconds later, I understood that 4

[@user-ri6rn7ti5h]

a(8

[@rubiconklbrutorowman7577]

U did not simplify saying log 12 divided by log 3 will give 2.26 and then multiply 2.26 by 2 will give rounded up 4.52. This is click bate, but should not be in standard form of test, take too long, unfair did not say use log, cz take too long that time is too tight in standard test why question like this should not be in standard test, but good to get (click bate!), math teacher or not, everybody need something using U tube to get some recognition n few cents or more. All these steps would have been simpler if question stated use log! All these has zero connection in reality for vast plus people other than those forced to learn to go to college even then only top 5-ercent graduates, best of best, ever get their field gets job, why trade school is booming n I know even ex-electrical, mechanical engineering major ended up going to trade school to obtain automotive certifications to be auto technician how highly computerized and must have at least fair understanding of electrical knowledge... This math is totally useless is my closing fact-based point indeed and case closed!

[@ssalim6286]

1+1= 11

[@krunoslavregvar477]

d) possibly?✓✓✓

[@thenubianspeaks4329]

You are really falling down on this one, dont' want to use a calculator, defeats the whole purpose., You are just wasting time. just stick to the present problem

[@jamescoe4765]

I get impatient with this teacher. Its a log problem so just get to it! I get it, you are trying to confuse new students with too many ideas and scribbles.

[@Basman59]

Utter ridiculous to take 20 mins for what took me literally 3 seconds to do it twice. I had to make sure as it was so easy. This guy is laughable. He would have flunked 11+ for not answering in the time allotted. So bloody remedial it’s beyond a joke if people can’t do this - it’s simple multiplication. Oh wait, I know someone who can’t do this his initials are DT.

[@Rastafire1379]

Smh. Very annoying

[@user-om1be6qb4h]

I really wish you would just show how to solve the problem and not talk so much!

[@lawrencemoore2414]

I wouldn't last 45 mins in his maths class, so boring!

[@marcjasinski3998]

He talks and talks and talks........

[@jayswartzentruber7650]

This is why math is so fucked up. There could be 2 more different ways to solve this. Plug that number that number back into the equation. Then tell me what you come up with.

[@suzanne9622]

4.52

[@llywyllngryffyn8053]

D

[@bertmoore4092]

8

[@shahdeen4444]

24

[@samswift4921]

D

[@kennethwright870]

D

[@carolstones2604]

8