Duration 3:30

A tricky exponents problem from the UK

by MindYourDecisions

245 348 watched

9.5 K

Published 2021/05/29

Students in the UK faced a similar question to this one. Don't give up--U can solve it! Adapted from https://www.reddit.com/r/HomeworkHelp/comments/de402k/gcse_edexcel_further_math_how_would_you_solve_for/ Subscribe: /user/MindYourDecisions Send me suggestions by email (address at end of many videos). I may not reply but I do consider all ideas! If you buy from the links below I may receive a commission for sales. (As an Amazon Associate I earn from qualifying purchases.) This has no effect on the price for you. My Books (worldwide links) https://mindyourdecisions.com/blog/my-books/#worldwide My Books (US links) Mind Your Decisions: Five Book Compilation https://amzn.to/2pbJ4wR A collection of 5 books: "The Joy of Game Theory" rated 4.2/5 stars on 189 reviews http://amzn.to/1uQvA20 "The Irrationality Illusion: How To Make Smart Decisions And Overcome Bias" rated 3.9/5 stars on 16 reviews http://amzn.to/1o3FaAg "40 Paradoxes in Logic, Probability, and Game Theory" rated 4/5 stars on 28 reviews http://amzn.to/1LOCI4U "The Best Mental Math Tricks" rated 4.1/5 stars on 53 reviews http://amzn.to/18maAdo "Multiply Numbers By Drawing Lines" rated 4.1/5 stars on 22 reviews http://amzn.to/XRm7M4 Mind Your Puzzles: Collection Of Volumes 1 To 3 https://amzn.to/2mMdrJr A collection of 3 books: "Math Puzzles Volume 1" rated 4.4/5 stars on 67 reviews http://amzn.to/1GhUUSH "Math Puzzles Volume 2" rated 4.2/5 stars on 19 reviews http://amzn.to/1NKbyCs "Math Puzzles Volume 3" rated 4.2/5 stars on 15 reviews http://amzn.to/1NKbGlp 2017 Shorty Awards Nominee. Mind Your Decisions was nominated in the STEM category (Science, Technology, Engineering, and Math) along with eventual winner Bill Nye; finalists Adam Savage, Dr. Sandra Lee, Simone Giertz, Tim Peake, Unbox Therapy; and other nominees Elon Musk, Gizmoslip, Hope Jahren, Life Noggin, and Nerdwriter. My Blog https://mindyourdecisions.com/blog/ Twitter https://twitter.com/preshtalwalkar Merch https://teespring.com/stores/mind-your-decisions Patreon https://www.patreon.com/mindyourdecisions Press https://mindyourdecisions.com/blog/press

الكلمات

Mathematics

Math

Maths

Riddle

Brain teaser

Puzzle

Math puzzle

Comments - 1060

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@davidhiggins5132منذ 3 سنوات "let's take a look at 3 to the power of x. 'U' can solve it"
"Uhhh no I can't. Oh that U" 252
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@jagmarzمنذ 3 سنوات I think it's more satisfying to say the answer is log3(5) - 1. 837
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@fongalex6639منذ 3 سنوات Thanks and this is one of the easiest question in this channel! 831
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@omerbulduk6628منذ 3 سنوات this is the first question that i solved in this channel before watching the solution and today is my birthday :) 315
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@jorgetodeschini5446منذ 3 سنوات I love it when he throws in an easy question every now and then! 2
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@xactlyincمنذ 3 سنوات I think taking log3 gives a more beautiful answer since we are dealing with two 3's 56
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@daanvoets4125منذ 3 سنوات before i found your channel i felt confident about my math skills 5
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@benzoredمنذ 3 سنوات I wish I had seen this video while I was still teaching college algebra. It's a great way to incorporate all the skills from that class. 16
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@tony2637منذ 3 سنوات Almost the same way but my answer is “Log3 (5/3)” 105
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@adityayalagoor2010منذ 3 سنوات This was one of fewest questions on this channel, that I could solve. Good one. 7
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@Ryan_but_the_name_was_takenمنذ 3 سنوات It’s been 13 years since I’ve done any form of math like this but it all comes back somewhat when seeing familiar style equations. 1
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@ponnshaa2007منذ 3 سنوات Learnt logarithmic stuff a few days ago and this was a good way to test myself. Thanks 5
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@vidblogger12منذ 3 سنوات Dang, here I thought I was special for getting this one. Looks like it's actually not that hard to spot the quadratic. 27
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@tjohnson4062منذ 3 سنوات I've been watching your videos for a while now and I have to say that I might not be any better with math but I am about 300% more humble. I think id="hidden2" class="buttons"> I might have solved around 3 of the 15+ I've watched. If I keep watching I should be ready to donate my organs for research due to the rapid decline in self-confidence. ....وسعت 2
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@sallychi8406منذ 3 سنوات The "non-real" answer to 3^x = -3 should be 1 + (πi / ln 3), since ln(-1) = πi. 25
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@bambi3886منذ 3 سنوات Whenever this type of question came out in exam. I'd give up immediately. but thank you for making this video. I'm enlightened 3
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@lady0shadyمنذ 3 سنوات Wow, I'm so glad that I still remember basics and solved this one. ❤️ 2
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@sohangundoju8940منذ 3 سنوات without even any background IITians are used to seperating and solving it as a normal quadratic.very easy for most MPC students 41
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@overlordprincekhanمنذ 3 سنوات This is the type of Maths that I could solve very easily 12
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@stevebitar7012منذ 3 سنوات Thanks Presh! Nice problem. Q. Why stop at real values of x? The complex solution is fun to solve for: x=i(pi)/ln3 +1 Great review of logarithms for me. 1
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@Robi2009منذ 3 سنوات "You can solve it"
No, I can't
"U is equal to 3^x"
Hahaha, very funny :/ 28
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@mohamedamr1351منذ 3 سنوات Thanks for the wide range of questions
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@user-dp9yn7zf4lمنذ 3 سنوات yr10 math teacher should show this to their student
a brilliant question covers both quadratic and logarithm 2
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@charliehe4542منذ 3 سنوات I see that MindYourDescision has been posting more easier questions recently as confidence boosters. Thanks.
A more easier solution is to mu id="hidden4" class="buttons">ltiply the equation by 3 and you have 3^(2x+2) + 4*3^(x+1) - 45 = 0. Then substitute 3^(x+1) = y, we have y^2 + 4y - 45 = 0, which we can factorize by simply eyeballing. ....وسعت 4
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@advaymayank1410منذ 3 سنوات I have been watching your videos and could solve this one with ease. Thankyou for these videos! 2
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@lighthouse3731منذ 3 سنوات the only question of this Youtuber that I can solve without watching the entire video. 1
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@akhladmehboobمنذ 3 سنوات Solved it without watching first time feeling proud Thanks for these problems 1
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@samuelpierce9962منذ 3 سنوات Once you recognize it's a quadratic you just have to work out the algebra. I used log base 3 though. Fun puzzle 2
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@nyfyre3768منذ 3 سنوات we did this in math class on Tuesday!
not this exact problem, but this concept 1
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@GamingDragon07منذ 3 سنوات When you realise it's u can solve it and not you can solve it 9
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@markgillespie3971منذ 3 سنوات Nice problem. I did it slightly differently, multiplied through by 3 at the start then used U = 3^(x+1) as substitution
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@DanielWalvinمنذ 3 سنوات At , taking log_3 of both sides instead of ln:
log_3(3^x) = log_3(5/3).
x log_3(3) = log_3(5) - log_3(3).
x = log_3(5) - 1.
Less likely to be able to use your calculator on it to get a numerical answer, but simpler and looks better. ....وسعت 1
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@doudouherve1248منذ 3 سنوات Thanks for this. I just need to know which application are you using to make this kind of video
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@neutron417منذ 3 سنوات The trend of algebra Questions in this channel is towards the easier side especially this one was one of the easiest 1
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@yurineuro9048منذ 3 سنوات Really liked the smooth graphical illustration. Does anyone know what type of software has been used? 2
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@noogler123منذ 3 سنوات I see every equations as a quadratic equations first 50
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@guobinsee6916منذ 3 سنوات in Malaysia already existed this type of question more than 10 years, can refer past year of SPM Add Maths questions/ chapter name: Indices and Logarithm
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@shaparmy465منذ 3 سنوات So, I am a bit confused here. When can we use natural log and When is log must be used?If these two terms are used for this question,will both result in the same answer? Thanks! 1
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@marx5740منذ 3 سنوات Hey, I wish you can tell in the beginning of the problem on what mathematical knowledge I need to solve it. I wanna solve these problems but I haven't learned about it yet.
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@tonyennis1787منذ 3 سنوات What mental leap made you choose the `u=3x` technique (starts around ) ? That's what I missed. manipulating the symbols I can do. But knowing which technique. not so much. ....وسعت
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@szyszak3338منذ 3 سنوات I am from Poland and I am in highschool.
Such equations are here very popular and we do them normally.
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@takeshiasahi5494منذ 3 سنوات Dono . I just went rogue and put x= 1/2. Kinda worked at integer level but not at decimal, (extra 0.9 was left ). How ironic. 3
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@Roarshark12منذ 3 سنوات Nice, very straight-forward :) thanks for this!
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@parthosaha4170منذ 3 سنوات The first problem I was able to solve of this channel 1
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@pomi6320منذ 3 سنوات Through my thesis, doing this the actually medieval mathematical way and the way that o was taught by Cambridge international advanced examination in Britain. It will be 0.73516. Log3(3 square root 2 then -2) = 0.73516 1
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@ardnys35منذ 3 سنوات that one was simple but it's always satisfying when these stuff turn into quadratics. i have been solving quadratics for years and it's still satisfying 5
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@jacobzinka7401منذ 3 سنوات As soon as I saw the +1 to the 2x exponent, I knew the answer 1
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@marseille3252منذ 3 سنوات About to take my Add Maths exam and am glad that I could solve this
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@adityaseth_777منذ 3 سنوات Already solved without watching. But nice one. Your videos are really great 38
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@urkanchhaمنذ 3 سنوات these are the very common problems asked in our middle school every annual exam
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@LucasPretiمنذ 3 سنوات Thanks for the thumbnail, I managed to do it in my head 2
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@sumansharma9857منذ 3 سنوات We used to solve these type of quadratic equations in 9th standard . I considered 3 to the power x as a .. we used to solve so many sample exam papers that it came so naturally..
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@scoobydoo75منذ 3 سنوات if we are taking square on both sides i.e. u^2 = (3^x)^2 so on R.H.S, it should become 9^2x because we took square of (3^x) as a whole. I am a bit confused at that point 1
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@DARKNESSrbgمنذ 3 سنوات This is one of the easiest problems on this channel and I didn’t even know where to get started
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@muhammadsiddiqui2244منذ 3 سنوات Did it instantly, just because studied this in college, "equations reducible to the quadratic form".
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@muradmuhammed9441منذ 3 سنوات You are wonderful thanks for your efforts
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@abhilashpatel3036منذ 3 سنوات The only question i was able to crack on this channel. 1
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@LocalDandrew92منذ 3 سنوات I made my own question but I don't know the answer.
A game of chess is played with a 500 elo human and a 550 elo bot. The timer is infinite. What is the expected number of moves the game lasted? 1
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@sgcomputacionمنذ 3 سنوات Thank you for giving me the opportunity to believe that I am an excellent mathematician
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@rishiaman2288منذ 3 سنوات i treated the 3 as z and used the quadratic equation 16
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@rameshkr6490العام الماضي Why do you take natural log of both sides instead of any other log such as log base 10? They both have the same results after all. Thank You.
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@thomjanssen8115منذ 3 سنوات The last is much more easy! Just applying the rules: gives x = log3(5/3) = 0.465 the eact same answer 1
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@weebcells2391منذ 3 سنوات Thanks for the questionn
It was the easiest one I ever found on your channel
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@madhurawat155منذ 3 سنوات I was able to solve it till 3^x = 5/3, I just haven't studied log yet. 6
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@lapprenticeمنذ 3 سنوات Lemme guess while I'm driving: substitution 3^x as another abstract unknown then solve standard quadratic 2
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@piman9280منذ 3 سنوات Hallelujah - Presh finally called it "The Quadratic Formula!"
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@niccolocervelli7569منذ 3 سنوات I actually did it, now I'm feeling smart 1
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@omplayschessمنذ 3 سنوات Omg you are a pro man. I watched him accidentally and Now I watch him regularly.
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@christianvanderstap6257منذ 3 سنوات Dear lord, I have forgotten a lot over the years. 3
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@mushfikaikfatمنذ 3 سنوات Perhaps one of the easiest problems you've solved so far XD
I've already solved it without watching
Love from Bangladesh ♥️ 2
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@MrRobbertJمنذ 3 سنوات I have a riddle for you:
Two trains, Train A and Train B, simultaneously depart Station A and Station B. Station A and Station B are 252.5 miles id="hidden16" class="buttons"> apart from each other. Train A is moving at 124.7mph towards Station B, and Train B is moving at 253.5mph towards Station A. If both trains departed at 10:00AM and it is now , how much longer until both trains pass each other? ....وسعت
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@andyiswonderfulمنذ 3 سنوات Easy one. Did it exactly like you did.
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@shilamondal1940منذ 3 سنوات It is a simple one but good for learning quadratic equations
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@atulkumar-lx6hgمنذ 3 سنوات this cn be solved by taking 3pwerx as y and the eq will be reduced in quadratic form 3 y square + 4y-15=0
which gives two value and the -ve will be discarded only +ve will be taken.
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@creativators9675منذ 3 سنوات I think it's the 2nd or 3rd question of quadratic equation chapter. 3
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@muh.rofiadhimrajab8375منذ 3 سنوات 3^x = 5/3
Using the logaritma form
a^b = c
a log c = b (a is basis)
then, the solution is
x = 3 log (5/3)
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@abhishekpatil1063منذ 2 سنوات The values of X are
X=[1+i(pi)(2n+1)]/log3
and X =[ log (5/3)+2ipin]/log3
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@dheerajsamota5194منذ 3 سنوات This question is like the basic question which u are taught in quadratic equations in topic pseudoquadratic if u are preparing for jee
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@aaryunikمنذ 3 سنوات Satisfaction: when you are able to solve a MindYourDecisions problem before moving on to the video
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@georgepapakostas7292منذ 3 سنوات I literally figured it out by completing the square which was more complicated but yielded the same result. The only part I couldn’t figure out was the log cause ive never learned it!! So close lol!!
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@chris-ph6soمنذ 3 سنوات you can't write that 3(3^2x) = 3^2x+1 because if we multiple it out we got just 3^1•3^2x and we don't add those exponents we multiply thm so that would just be 2x
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@Jason-ot6jvمنذ 3 سنوات easy yet satisfying to solve. very nice lol
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@xeusمنذ 3 سنوات Others might've mentioned this already, but ln(5/3)=ln(5)-ln(3), and so you can simplify the answer to x=ln(5)/ln(3)-1. While you could represent ln(5)/ln(3) id="hidden20" class="buttons"> with 3-based log from 5, I think the answer with natural log and integers is the most beautiful one. ....وسعت
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@louisd95714منذ 3 سنوات Not too sure why I even watch these videos when I canot solve any of them. To those of you who can, good for you!
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@d4djangoمنذ 3 سنوات Thank you. You solved it exactly just like I did. But instead of 'u' I used 'y'. And instead of taking ln, I took log to the base 3. Which id="hidden21" class="buttons"> leaves evaluating, log 5 to base 3 minus 1 as the value of x. That cannot be done manually ....وسعت 6
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@joshuaprice1منذ 3 سنوات Please could you do a series for people who aren't quite as clever where you give us hints as how to find the answer. I could have done every equation id="hidden22" class="buttons"> in this but my intuition isn't good enough to find how to connect them together ....وسعت
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@awaanmustafa2257منذ 3 سنوات Jee aspirants solve almost every logarithmic and exponential equations by this method 1
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@lexus_bklمنذ 3 سنوات The same approach was done by you in your one of your videos: 4^x + 6^x = 9^x 1

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A tricky exponents problem from the UK

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الكلمات

Mathematics

Math

Maths

Riddle

Brain teaser

Puzzle

Math puzzle