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.

[@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

[@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.

[@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.

[@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

[@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.

[@pinkalex7703]

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

[@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

[@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

[@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.

[@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

[@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.

[@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 ?

[@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

[@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

[@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.

[@yiutungwong315]

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

[@larrywiener6327]

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

[@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

[@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.

[@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.

[@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

[@tigerhorn2954]

How do you solve this without a calculator?

[@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.

[@tonydolosa759]

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

[@usa40111]

D. 4.52

[@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.

[@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.

[@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

[@stevenjohnson1143]

D dividing it by 2 gives c

[@jimwalshonline9346]

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

[@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.

[@pamelabyars3983]

D) 4.42

[@Cariboolife]

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

[@Mike80097]

D by inspection

[@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!

[@boraorhan8398]

10 seconds later, I understood that 4

[@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". ;)

[@hasushah5290]

8

[@marknieuweboer8099]

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

[@normalucia9930]

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

[@davidwatson7604]

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

[@SUJAMUK]

8?

[@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

[@harpleblues]

First tip: scroll 3/4 of the way through the video Second tip: find another teacher

[@petergomes8788]

d..

[@maxkennedy5073]

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

[@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??

[@nobodymr.3605]

D

[@user-ri6rn7ti5h]

a(8

[@joseortalizsr8384]

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

[@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

[@shahdeen4444]

24

[@sriindrawati7572]

D. X =4,52

[@edjo487]

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

[@1961ebutuoy]

x = 50.3017

[@melvinthomas6349]

Too much time wasted in solving problem.

[@krunoslavregvar477]

d) possibly?✓✓✓

[@ssalim6286]

1+1= 11

[@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

[@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

[@lawrencemoore2414]

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

[@marcjasinski3998]

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

[@user-om1be6qb4h]

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

[@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

[@carolstones2604]

8

[@llywyllngryffyn8053]

D

[@bertmoore4092]

8

[@samswift4921]

D

[@kennethwright870]

D