How to Solve Logarithmic Equations with Different Bases - The Change of Base Formula

Тәжірибелік нұсқаулар және стиль

Learn how to Solve Logarithmic Equations with different bases using the Change of Base Formula. Also check your answer for extraneous solutions. Step-by-Step Explanation by PreMath.com

Пікірлер: 129

  • @harshmaurya3848
    @harshmaurya38482 жыл бұрын

    A man who makes totally time wasting short videos has 10 million subscribers in his channel but this channel is really awesome and has only approx 2 lakh. Not fair yaarrr

  • @ddouglas8161
    @ddouglas81612 жыл бұрын

    I love this. One thing I wanted to add to gues video is that being log8(x) and log16(x) have base 2 in common, we could rewrite it as log2^3(x) and log2^4(x) and identifying a log base value would be the denominator when the change of base is applied, we could then rewrite the equation as 1/3log2(x)-1/4log2(x) and then proceed from there.

  • @pierrepicard762

    @pierrepicard762

    Жыл бұрын

    0pplp0pd0lo 0poppp0pp0

  • @prathamdivyansh2376

    @prathamdivyansh2376

    Жыл бұрын

    And further take value of log2(x) to be t solve t it only gives one value which is 1 and solve less lengthy

  • @johnporcella2375
    @johnporcella2375 Жыл бұрын

    Excellent tutorial covering, ahem, a lot of bases! No pun was intended!

  • @damianmatma708
    @damianmatma7084 жыл бұрын

    00:00 It is even more simple when you use the formula: log.(a^m) (x) = (1/m) * log.a(x) Hence you get: log.8(x) - log.16(x) = 0 log.(2^3)(x) - log.(2^4)(x) = 0 (1/3) * log.2(x) - (1/4) * log.2(x) = 0 Now it is quite simple: [ (1/3) - (1/4) ] * log(x) = 0 [ (4/12) - (3/12) ] * log(x) = 0 (1/12) * log(x) = 0 || *12 log(x) = 0 log.10(x) = 0 x = 10^0 x = 1 "1" is the solution, because it is in the Domain which is D: x>0

  • @unonovezero

    @unonovezero

    4 жыл бұрын

    I came up with the same solution as yours, before watching the video and comments. It's quicker and without unuseful steps.

  • @nadeekaekanayeka.9347
    @nadeekaekanayeka.93472 жыл бұрын

    The lesson is well understood sir,thanks a lot.

  • @sanelephungula8780
    @sanelephungula87804 жыл бұрын

    For those of you telling sir that he could have solved the problem in three steps keep your mouth shut, he's a professor he knows wat he's doing and his intentions was to clearly illustrate for students that might not readily know how to go about solving this problem problem, thank you.

  • @PreMath

    @PreMath

    4 жыл бұрын

    Thank you so much! Please keep supporting my channel. Kind regards 😀

  • @mekdalwityoseph1100

    @mekdalwityoseph1100

    3 жыл бұрын

    All humans have mistake except Lord Jesus and his mother virgn Mary and being professer doesn't make him knowing every thing and not to do mistake expect tirinty lord

  • @EE-Spectrum

    @EE-Spectrum

    2 жыл бұрын

    I strongly disagree with you. In an exam students need the shortest possible mathematical way to solve problems. They don't need complicated methods and he being a professor should know that.

  • @global-linkacademicagency2156

    @global-linkacademicagency2156

    Ай бұрын

    Just because he's a professor doesn't make everyone else an idiot.

  • @GreatBearLullaby
    @GreatBearLullaby Жыл бұрын

    I love this. Two logs have different base and are equal. How's that? So that x = 1. Just because no other points where different-base logs can meet. Telling this basic story during nine minutes - great.

  • @matthewtaylor8102
    @matthewtaylor8102Ай бұрын

    Change of base, seems to suggest Gauge equation: unit conversion transform method. Conductance, energy, conversion and energy transform ascertained. Thanks and have a nice day, thank you Sam.

  • @natashachisenga9524
    @natashachisenga95242 жыл бұрын

    I need some of your previous videos on logs

  • @kabelingo5418
    @kabelingo5418 Жыл бұрын

    There is a short solution. You solve the right side y= log.16 (x) by taken it to the base (2*8) . y is only a placeholder for the watched term. So (2*8)^y=x eq(1). This can be simplified to 2^y*8^y=x (eq2). Now the left side is taken to base 8. So y=log.8 (x) becomes 8^y=x eq(3) , which can be written as 2^y*2^y*2^y=x. Now taken the 3. root from that: 2^y=3.root(x) (eq4) eq(3) and eq(4) we set in eq(2) and we get 3.root(x)*x=x. We can see the possible solution are x=0 and x=1. But x=0 is no solution, because the original equation get infinity. It remains x=1

  • @zolisaganyile1128
    @zolisaganyile11282 жыл бұрын

    So far so good 👍

  • @john-phimcmelley6422
    @john-phimcmelley6422 Жыл бұрын

    The log function is not defined on the interval ]-∞, 0]. You MUST state that BEFORE begining any calculus, hence excluding 0 as a solution. Thus checking the answer x=0 as you do is unnecessary (not to say wrong).

  • @jaaaayt.20
    @jaaaayt.203 жыл бұрын

    i liked and watched the video sir

  • @PreMath

    @PreMath

    3 жыл бұрын

    Thanks. You are awesome.

  • @abdurahmanmuse2941
    @abdurahmanmuse29412 жыл бұрын

    Really, exciting Vedio 🔥😇

  • @sriiniketansridhar1944
    @sriiniketansridhar1944 Жыл бұрын

    Sir, usually when doing this problem you also have to add two with log of x

  • @renewd
    @renewd3 жыл бұрын

    I used log.2 when using the change of base formula, this eliminated many of the steps. i only arrived at 1 solution, x = 1.

  • @tapatirudrapal5586
    @tapatirudrapal55864 жыл бұрын

    u have made it an equation history.it could be solved more easierly

  • @Kidaniekidanie
    @KidaniekidanieАй бұрын

    Thanks a lot sir,

  • @kyikyilay6119
    @kyikyilay6119 Жыл бұрын

    Thank you so much .

  • @anandamondal6092
    @anandamondal60922 жыл бұрын

    At starting point can be eliminate logx from boths side, then how can get x value?

  • @nasimultafim765
    @nasimultafim7652 жыл бұрын

    Had a confusion about the base changing of a logarithm. It totally solved the problem. Appreciate it👏

  • @hungryfareasternslav1823
    @hungryfareasternslav18235 жыл бұрын

    Sir, you don't need to do that long since log_n(1)=0

  • @giovannisala9242
    @giovannisala92422 жыл бұрын

    Lo scopo dell'esercizio proposto e la sua soluzione, è anche di mostrare molte belle proprietà dei logaritmi e le molte ed eleganti vie del calcolo.

  • @charlotteserimbi4862
    @charlotteserimbi48625 жыл бұрын

    May God almighty bless you

  • @jim2376
    @jim2376 Жыл бұрын

    This guy is an excellent teacher.

  • @misterywhawee8182
    @misterywhawee81823 жыл бұрын

    Can you say that cause X^3 = X^4 so it have to be 1 and 0 otherwise its not possible?

  • @Awesome-ct7vr
    @Awesome-ct7vr2 жыл бұрын

    What i did at the end where we have: X^⅓ = X^¼ is: Divide both sides by X^¼ X^⅓/X^¼=1 Move the X^¼ to the numerator and get: X^⅓*X^-¼=1 X^1/12=1 (X^1/12)^12=1^12 X=1

  • @ruthmuhambe776
    @ruthmuhambe776 Жыл бұрын

    Thanks for that

  • @jonathanaryee3505
    @jonathanaryee35054 күн бұрын

    I didn't do it that same way but still had an answer. I got to a part of 4INX - 3INX which is equal to zero. Then I subtracted 3 from 4, which which made it e of x is equal to zero. Then I had x to be one.

  • @aakashkarajgikar9384
    @aakashkarajgikar93842 жыл бұрын

    Dude! I did it the easier way out. First, what I did is, used the change of base formula ; then rewrote 16 as 2^4, and 8 as 2^3 ; then I used the power rule of logs "log(n^b) = b * log(n)" ; then I multiplied both of the fractions to get common denominators ; then I set just the numerator equal to zero after setting the whole fraction equal to 0 ; then I used the power rule of logs in reverse "b * log(n) = log(n^b)" ; then I used the quotient rule of logs ; then I used the quotient rule of exponents within the logs ; then I set log(x) to be equal to log(x) with base 10 ; then I converted to exponential form ; then noticed 10^0, which is equal to 1, and that is equal to x. What you are doing is the longer way out. you are checking for more possible solutions, but they are extraneous, so it would have been better if you did what I did no?

  • @Demi305
    @Demi305 Жыл бұрын

    I have a Little doubt, sir At 6:30, you got X⁴ = X³, so as the bases are equal, we get 4 = 3 but 4 ≠ 3, I am a bit confused, could you please reply However, Thank you very much for this amazing video, I have been actively watching a lot of your videos and they have really amazed me! Keep it up! hope to see more!

  • @unnati_hulke

    @unnati_hulke

    Жыл бұрын

    If you try putting up the value of x as 1 or 0, the equation X³ = X⁴ will become valid, as we know, 1 to the power of n = 1; thus X³ = 1; X⁴ = 1; hence X³=X⁴ And. For x=0, 0^n = 0. Hence X³ =X⁴ =0 This won't work out on other values, except for 0 and 1... Hope you got my point....

  • @muhammadtareq6253
    @muhammadtareq62535 жыл бұрын

    Hi Sir, just wonder about this part x^4 = x^3, Couldn't you just divide both sides by x^3 so you could find just the true answer right away? Thanks anyway way.

  • @albertmendoza1468

    @albertmendoza1468

    5 жыл бұрын

    x^4=x^3 is not possible

  • @tigerbeast3406

    @tigerbeast3406

    5 жыл бұрын

    @@albertmendoza1468 It's possible if x is equal to 0 or 1

  • @SrisailamNavuluri

    @SrisailamNavuluri

    5 жыл бұрын

    When x=0,you are dividing by 0.

  • @war_reimon8343

    @war_reimon8343

    5 жыл бұрын

    @@tigerbeast3406 0 is not possible because it is undetermined. So it leaves only possible the one.

  • @tigerbeast3406

    @tigerbeast3406

    5 жыл бұрын

    @@war_reimon8343 You must factor it to find all the real solutions x^4 = x^3 x^4 - x^3 = 0 (x^3)(x - 1) = 0 (factoring x^3) The two solutions are: x^3 = 0 or x - 1 = 0 Therefore from the first equation x = 0 and from the second we get x = 1

  • @war_reimon8343
    @war_reimon83435 жыл бұрын

    Only 1 fulfills the equation.

  • @josepmadrid5400
    @josepmadrid54002 жыл бұрын

    These people were trying to outsmart the teacher.really? Why waste watching if you know already and know quick solution? ..this lecture is for those students or person who has difficulty and willing to understand it step by step. Just be humble guys, make ur own KZread channel..

  • @johngreen3543
    @johngreen35432 жыл бұрын

    Instead of using base 10 it is easier if you use base 2 on the change of base

  • @charlotteserimbi4862
    @charlotteserimbi48625 жыл бұрын

    I am understanding

  • @ramanivenkata3245
    @ramanivenkata32453 жыл бұрын

    Fantastic explanation 👍

  • @PreMath

    @PreMath

    3 жыл бұрын

    So nice of you Ramani dear! You are awesome 👍 I'm glad you liked it! Please keep sharing premath channel with your family and friends. Take care dear and stay blessed😃

  • @JLvatron
    @JLvatron2 жыл бұрын

    At 1:34, you have Log X on both sides. If we divide by this we will have 1/Log 8 = 1/Log 16. How can this be?

  • @JLvatron

    @JLvatron

    2 жыл бұрын

    @@XJWill1 Thanks!

  • @jemanishajones9707
    @jemanishajones97073 жыл бұрын

    I watched and liked it

  • @PreMath

    @PreMath

    3 жыл бұрын

    Thanks. You are awesome.

  • @sriramtejapalika3605
    @sriramtejapalika36052 жыл бұрын

    Sir, can you do this problem

  • @damianmatma708
    @damianmatma7084 жыл бұрын

    03:45 You should rather put this "(1/4)*log(x)" form the right side to the left side (with the sign "+" changed to "-"): (1/3)*log(x) = (1/4)*log(x) (1/3)*log(x) - (1/4)*log(x) = 0 [ (1/3) - (1/4) ] * log(x) = 0 [ (4/12) - (3/12) ] * log(x) = 0 (1/12) * log(x) = 0 || *12 log(x) = 0 log.10(x) = 0 x = 10^0 x = 1 "1" is the solution, because it is in the Domain which is D: x>0

  • @henrydavis8910
    @henrydavis89104 жыл бұрын

    It was obvious from the beginning that log x = 0, meaning x = 1, because the only way that raising x to two different powers gives an equality is if x = 1. This fellow used a sledgehammer to kill a fly. Far too complicated, tedious, and unnecessary.

  • @geoellinas

    @geoellinas

    2 жыл бұрын

    Yes. The charm of mathematics is in finding the shortest path!

  • @john-phimcmelley6422

    @john-phimcmelley6422

    2 жыл бұрын

    I agree. And whatever the base is, log 0 is undefined, so the solution x=0 must be rejected before any calculus. (Always check the domain before starting !)

  • @humphreyfrog2045

    @humphreyfrog2045

    2 жыл бұрын

    @@geoellinas I think the charm of mathematics is paths

  • @geoellinas

    @geoellinas

    2 жыл бұрын

    @@john-phimcmelley6422 For mathematicians yes. But for the students I believe what I said.

  • @gregnixon1296

    @gregnixon1296

    2 жыл бұрын

    It amazes me how many answers are -1, 0, or 1.

  • @dadsprincess158
    @dadsprincess1583 жыл бұрын

    Sir please give solution for this If log a basex=log b base x thena=b if where a>0^b>0^ x>0 x is not equal to 1

  • @PreMath

    @PreMath

    3 жыл бұрын

    Hello Eshwaraiah, here is the proof: Our LHS: log a basex=log b base x => use the change of base formula: (loga)/(logx) = (logb)/(logx) => both denominators get cancelled => loga = logb => use equality rule: a=b RHS. Hope it helps. If you want I can upload video for you as well. Take care and all the best😃

  • @tryyourbest3162
    @tryyourbest3162 Жыл бұрын

    I am Bangladeshi 🥰🥰🥰 thanks a lot ❤️

  • @thichhochoi766
    @thichhochoi766 Жыл бұрын

    At 2:59 log (x)/a = log(x)/b is impossible unless log (x) = 0 or x=1.

  • @edwinalexander1170
    @edwinalexander11705 жыл бұрын

    X should only be equal to 1 sir as log of zero to any base is under define

  • @ItumelengS

    @ItumelengS

    5 жыл бұрын

    Yep, and it can only be one value as it's only x^1

  • @MS-cj8uw
    @MS-cj8uw5 жыл бұрын

    Sir the solution is maximum 3 steps only ....

  • @homayounshirazi9550

    @homayounshirazi9550

    5 жыл бұрын

    We used to get points taken off for "excessive math!"

  • @charlynecharles8649

    @charlynecharles8649

    5 жыл бұрын

    hes trying his best, so dont be so rude

  • @jennybenson9562

    @jennybenson9562

    5 жыл бұрын

    can you explain to me how it is easier? I am in a math class at my college and I want to understand how it can be done in 3 steps

  • @ziadahmed6955

    @ziadahmed6955

    5 жыл бұрын

    Form the very begining you can take logx as a common factor then you will see that log x times 1/log8 minus 1/log16 equal zero which means that logx equal to zero therefore x equal 1

  • @tapatirudrapal5586

    @tapatirudrapal5586

    4 жыл бұрын

    @@jennybenson9562 o .i see.u r in college but also u r not able to use a simple logarithmic equation

  • @tonyhoanghp
    @tonyhoanghp Жыл бұрын

    Good

  • @timtran7756
    @timtran77563 жыл бұрын

    thanks

  • @PreMath

    @PreMath

    3 жыл бұрын

    You're welcome Tim! Thank you. You are awesome😀 Keep smiling😊 Enjoy every moment of your life 🌻

  • @luyandomweemba4103
    @luyandomweemba41033 жыл бұрын

    Amazing..

  • @PreMath

    @PreMath

    3 жыл бұрын

    Thank you so much luyando mweemba for taking the time to leave this comment. I'm glad you liked it! Your feedback is always appreciated. Please keep supporting my channel. Please stay connected. Take care dear 😃

  • @samriddhbhattacharyya6350
    @samriddhbhattacharyya63502 жыл бұрын

    I think we can solve this problem in another way avoiding all the complicated calculations Logically how can the power of 8 and 16 be same for the same value unless the value is 1 and power is 0 hence x has to be equal to 1

  • @thinklogically3081
    @thinklogically3081 Жыл бұрын

    I think x = {0,1,2,3,4,5,6,7} , what is your idea

  • @AmirgabYT2185
    @AmirgabYT21853 ай бұрын

    x=1

  • @user-sd6lo8zc5q
    @user-sd6lo8zc5q Жыл бұрын

    Why do you go long distance

  • @amitavadasgupta6985
    @amitavadasgupta6985 Жыл бұрын

    Log of x base2=0=>2^0=x=>x=1

  • @shanaya9876
    @shanaya98762 жыл бұрын

    I almost solved this but got stuck at the end cause of splitting of x4-x3😅

  • @sriramtejapalika3605
    @sriramtejapalika36052 жыл бұрын

    3^(x-1) =5

  • @gelbkehlchen
    @gelbkehlchen2 жыл бұрын

    Solution: (1) log8(x) - log16(x) = 0 According to logc(y) = loga(y)/loga(c) = same base (number/base), the following applies: log16(x) = log8(x)/log8(16) | applied in equation (1), results in: (1a) log8(x)-log8(x)/log8(16) = 0 |*log8(16)≠0 ⟹ (1b) log8(x)*log8(16)-log8(x) = 0 ⟹ (1c) log8(x)*[log8(16)-1] = 0 |/[log8(16)-1]≠0 ⟹ (1d) log8(x) = 0 ⟹ x = 8^0 = 1 Lösung: (1) log8(x)-log16(x) = 0 Nach logc(y) = loga(y)/loga(c) = gleiche Basis (Numerus/Basis) gilt: log16(x) = log8(x)/log8(16) | in Gleichung (1) angesetzt, ergibt: (1a) log8(x)-log8(x)/log8(16) = 0 |*log8(16)≠0 ⟹ (1b) log8(x)*log8(16)-log8(x) = 0 ⟹ (1c) log8(x)*[log8(16)-1] = 0 |/[log8(16)-1]≠0 ⟹ (1d) log8(x) = 0 ⟹ x = 8^0 = 1

  • @pranavamali05
    @pranavamali052 жыл бұрын

    I got answer as 12

  • @ruilongsheng2845
    @ruilongsheng2845 Жыл бұрын

    log x/3log 2 =log x/4log 2, so log x=0, x=1😃

  • @kelticlago
    @kelticlago5 жыл бұрын

    C'est une farce?

  • @9mmomo

    @9mmomo

    3 жыл бұрын

    Ouais c’est farce, x=1

  • @buttsez4419
    @buttsez44195 жыл бұрын

    It was obvious Why complicate things

  • @user-if7ch7cv1v
    @user-if7ch7cv1v2 жыл бұрын

    Why the answer not x=1?

  • @faithelias2798
    @faithelias27982 жыл бұрын

    God loves you and he wants to save everyone, but in order for him to do that, you need to repent and be baptized. Also share his gospel with everyone you come in to contact with and keep his commandments 🙏🏾😘

  • @akashranjanmohapatra4302
    @akashranjanmohapatra43023 жыл бұрын

    Where will be 12

  • @daniel.gutierrez18333
    @daniel.gutierrez183334 жыл бұрын

    Can somebody solve 4^ = 2^x

  • @neelamsrivastava8577

    @neelamsrivastava8577

    4 жыл бұрын

    X=2

  • @senghour8043
    @senghour80435 жыл бұрын

    log(🐭) ×log(🐭) =[log(🐭)] ×2 or [log(🐭)]?😔😔

  • @daniel.gutierrez18333
    @daniel.gutierrez183334 жыл бұрын

    Can somebody solve 4^x = 2^x

  • @HoutarouOrekiOsu

    @HoutarouOrekiOsu

    4 жыл бұрын

    (2^2)^x = 2^x 2^2x = 2^x 2x = x 2x - x = x - x x = 0

  • @user-dk5hn5on2v
    @user-dk5hn5on2v6 ай бұрын

    Ok

  • @henriquevianna6875
    @henriquevianna68753 жыл бұрын

    Elementary school math

  • @hmza7227
    @hmza72272 жыл бұрын

    diwiiided buy

  • @giuseppemalaguti435
    @giuseppemalaguti4352 жыл бұрын

    forse 1

  • @mulinakashala1st821
    @mulinakashala1st8214 жыл бұрын

    mind twisted already

  • @AthenaFidelia
    @AthenaFideliaАй бұрын

    Pliz h

  • @AnuragYadav-zk5pe
    @AnuragYadav-zk5pe5 жыл бұрын

    haaa

  • @patrickstewart6090

    @patrickstewart6090

    5 жыл бұрын

    log x 8 = 3/2 how to solve

  • @user-yz3oq2fh3x

    @user-yz3oq2fh3x

    5 жыл бұрын

    x^(3/2)=8 x=8^(2/3) 8^(2/3)=(8^(1/3))^2=2^2=4 x = 4 and, 4^(3/2)=8 Q.E.D (actually, this problem's solution is logarithme's definition.)

  • @mohamudmohamedyusuf2858

    @mohamudmohamedyusuf2858

    4 жыл бұрын

    @@user-yz3oq2fh3x xnxc

  • @Darkdesires946
    @Darkdesires9462 жыл бұрын

    Why is it so confusing😂

  • @HHH-tt5sb
    @HHH-tt5sb3 жыл бұрын

    حلك غير صحيح ﻻن المعادلة ﻻتتحقي اﻻ عندماx تساوي الصفر

  • @giuseppemalaguti435
    @giuseppemalaguti4352 жыл бұрын

    solo a vederla mi sembra non abbia soluzioni

  • @cuongtu6088
    @cuongtu60882 жыл бұрын

    it long

  • @doichekabano
    @doichekabano Жыл бұрын

    Воды много, автор объём нагоняет...

  • @oldsachem
    @oldsachem Жыл бұрын

    Too many steps.

Келесі