Solve Exponential Equation Using Logs

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  • เผยแพร่เมื่อ 26 ม.ค. 2025

ความคิดเห็น • 56

  • @Shmeve0
    @Shmeve0 7 ปีที่แล้ว +14

    Couldn't find this on Khan Academy! Thanks so much!

  • @LightPulsarCards
    @LightPulsarCards 8 ปีที่แล้ว +5

    I've been searching for hours on how to do this correctly. Thank you so much; it really helped.

  • @MrCaryMath
    @MrCaryMath  13 ปีที่แล้ว +1

    @ChelseyKryou, I assume you are referring to the step at 0:57. You are correct that (x^2)(x^3) = x^5, but in the example at 0:57 we are simplifying (2^3)^(2x+1) and in this case when you take a power to a power the exponents are multiplyed. The general rule looks like this: (x^a)^b = x^(ab). So (x^2)(x^3) = x^5 and (x^2)^3 = x^6. I hope that helps.

  • @dejawilson1632
    @dejawilson1632 10 ปีที่แล้ว +5

    You helped me so, much I could just give you a huge hug. Thank you

  • @sethchartier2556
    @sethchartier2556 4 ปีที่แล้ว +1

    You are a saint! I've been trying to figure this out for about a week and then i found this video. You saved my life XD

    • @MrCaryMath
      @MrCaryMath  4 ปีที่แล้ว

      So glad you found the video and it helped!

  • @MrCaryMath
    @MrCaryMath  12 ปีที่แล้ว

    You are doing great so far. Just to clarify, the original problem is 2^(x+3) = 3^(x-4). Your next step is to divide both sides by log3 - log2. As far as how to write the final answer it depends what the directions say. If they say to round to the nearest whatever, you can plug your answer into the calculator. If it says to give the exact answer you will want to simplify things using the rules of logs. For example 4log3 => log3^4 => log81, log3 - log2 => log1.5, also simplify the sum of logs.

  • @MrCaryMath
    @MrCaryMath  12 ปีที่แล้ว +2

    Wow, that's an interesting way to do the problem. It does work. If this method is easier for you I suggest you use it. My theory is that the easiest method is the one that you understand the best. Your method requires a few substitution steps that some might struggle with. I really appreciate seeing different approaches. Thanks for sharing!

  • @michaelk4150
    @michaelk4150 6 ปีที่แล้ว

    Thank you for the help man, studying for a final right now and gotta say, you going over the laws of exponents at the beginning really helped it click.

  • @autumndays7071
    @autumndays7071 11 ปีที่แล้ว +1

    Excellent video; very thorough and clear, and you explained why you did this and not that. Thank you so much.

  • @tbrown837
    @tbrown837 13 ปีที่แล้ว

    great job dude. this was so much more efficient than any of the times i tried to learn this in classes

  • @urinalturd
    @urinalturd 13 ปีที่แล้ว

    holy shit thank you i have been looking all through these damn videos and could never fing the exact approach i needed at 3:39 again thank you!!!!

  • @NewRepublicNoob
    @NewRepublicNoob 12 ปีที่แล้ว

    Hey man, I understand what you're doing and all and did great in my Homework until I came to this problem:
    2^x+3=3^x-4
    I did what you said and got this: (x+3)log2=(x-4)log3
    then got xlog2+3log2=xlog3-4log3
    I moved them to like sides and got: xlog3-xlog2=4log3+3log2
    Then got: x(log3-log2)=4log3+3log2
    What do I do on the right side, and how would I get the answer to this problem?

  • @Rodrigofrb
    @Rodrigofrb 12 ปีที่แล้ว

    Nice video. I found a different way to calculate it that is a lot easier.
    Just like on your example of that equation with similar bases(2^3X=8^2x+1), we can use log to calculate 9^X in the base of 5:
    5^Y = 9 and Y=Log5to9
    So Y = Log9/Log5 (To pass it all to the base of 10)
    So, back at the original equation:
    5^(x+2) = 5^(Log9/Log5)^x, which brings you to:
    X+2 = (Log9/Log5)^X, which can easily be calculated using a calculator, since it's all in the base of 10.

  • @connormeiering5921
    @connormeiering5921 6 ปีที่แล้ว

    fantastic explanation - Looked for a long time and this is awesome

  • @jetswhiteout961
    @jetswhiteout961 11 ปีที่แล้ว

    @rebym same idea. Use logs, there's just an extra step I think

  • @coleamster9837
    @coleamster9837 10 ปีที่แล้ว

    I was wondering if you could help me with a similar but more difficult problem. It is as shown below:
    4^x times 5^4x+3 = 10^2x+3
    Any tips would be appreciated!

  • @ChelseyKryou
    @ChelseyKryou 13 ปีที่แล้ว

    x^2 times x^3 doesnt equal x^6. It equals x^5. Since you use addition when it comes to exponential multiplicational integrers.

  • @helenepayne8971
    @helenepayne8971 4 ปีที่แล้ว

    Good video. You do not need a parenthesis around a product when dividing, eg (2log5)/log(9/5)=2log5/log(9/5). You would need a parenthesis if you had more than one term in the numerator.

  • @rebym
    @rebym 11 ปีที่แล้ว

    How would you solve if the problem was (2^x)+3=(3^x)-4

  • @falcaofan9
    @falcaofan9 12 ปีที่แล้ว

    Thanks man! I feel like this helped me more than my teacher haha

  • @dchen1010
    @dchen1010 9 ปีที่แล้ว +4

    thanks for the great explanation!

    • @MrCaryMath
      @MrCaryMath  9 ปีที่แล้ว

      +Daniel Chen you are welcome!

  • @yasminetayeh2973
    @yasminetayeh2973 4 ปีที่แล้ว

    I would give my understanding of this video a 3/4 because I understand why he made them both logs because he needed the same base of 10 but when he isolated the x it was kinda confusing so I wish he solved one more problem since I’m still kinda unfamiliar with it.

  • @biolexyable
    @biolexyable 13 ปีที่แล้ว

    thanks im still taking geometry but i get this cos you made it easy

  • @elinag5743
    @elinag5743 8 ปีที่แล้ว

    thanks! you teach well! your video helped me a lot :^)

  • @theoriginal4ever7
    @theoriginal4ever7 11 ปีที่แล้ว +1

    this was very helpful! thank you!!

  • @ryanpower9580
    @ryanpower9580 4 ปีที่แล้ว

    Why do none of these tutorials have anything on natural logs on both sides?

    • @MrCaryMath
      @MrCaryMath  4 ปีที่แล้ว

      I can do a video with natural logs on both sides. Would you like to a problem like 1) ln (something) = ln(something) or 2) ln(something) = ln (something) + #.

  • @trillking653
    @trillking653 5 ปีที่แล้ว

    yo, I saw in a video where if it is for example 2log5, the 2 goes to the exponent and its equal to log1/25. U forgot that step

  • @NewRepublicNoob
    @NewRepublicNoob 12 ปีที่แล้ว

    Please note I do not want the answer, I will figure that out myself, I just want to know what step comes after this.

  • @melissagarzon767
    @melissagarzon767 11 ปีที่แล้ว

    Omg ! this help me a lot ! Thank u

  • @4n0nym0uz
    @4n0nym0uz 12 ปีที่แล้ว

    you are the best!!

  • @ericandude
    @ericandude 13 ปีที่แล้ว

    i learned more than i did in 5 years of schooling...lol

  • @icrowbot
    @icrowbot 11 ปีที่แล้ว

    this was super helpful, thanks

  • @nta699
    @nta699 6 ปีที่แล้ว

    log(5/9) would give you a negative, and therefore your answer would be negative, correct?

    • @MrCaryMath
      @MrCaryMath  5 ปีที่แล้ว

      Yes log of (5/9) would be a negative number.

  • @cristinegalarza9929
    @cristinegalarza9929 10 ปีที่แล้ว

    THANK YOU!!! so helpful!!

  • @l3aIIin23
    @l3aIIin23 11 ปีที่แล้ว +2

    YOU SAVED MY LIFE

  • @severinus993
    @severinus993 4 ปีที่แล้ว

    Thank you so much

  • @jennya7352
    @jennya7352 10 ปีที่แล้ว +1

    Thank you sooooo much!!:)

  • @MrCaryMath
    @MrCaryMath  12 ปีที่แล้ว

    Excellent, glad it helped!

  • @fredzieplays8334
    @fredzieplays8334 2 ปีที่แล้ว

    thank you so much man

  • @dominickcarbone1772
    @dominickcarbone1772 11 ปีที่แล้ว

    Thank you very much.

  • @bbd0304
    @bbd0304 13 ปีที่แล้ว

    thank you sooooo much!

  • @whimsyspopit
    @whimsyspopit 3 ปีที่แล้ว

    did not undertsand anything. help

  • @daved1113
    @daved1113 4 ปีที่แล้ว

    thanks bro.

  • @zacp4658
    @zacp4658 8 ปีที่แล้ว

    THANK YOU!

  • @NewRepublicNoob
    @NewRepublicNoob 12 ปีที่แล้ว

    Okay, thanks, man :)

  • @Cindayyee
    @Cindayyee 13 ปีที่แล้ว

    bless you. thank you so so much! :)

  • @whimsyspopit
    @whimsyspopit 3 ปีที่แล้ว

    hoho

  • @cherryvanilla17
    @cherryvanilla17 12 ปีที่แล้ว

    thanks

  • @xXOMGXx1312
    @xXOMGXx1312 10 ปีที่แล้ว

    was

  • @willietenort6932
    @willietenort6932 7 ปีที่แล้ว

    blah blah*blah=blah

  • @senaytecle2467
    @senaytecle2467 10 ปีที่แล้ว +1

    thank you so much!