Solving logarithmic equations by factoring

Sdílet
Vložit
  • čas přidán 6. 12. 2011
  • 👉 Learn about solving logarithmic equations. Logarithmic equations are equations involving logarithms. To solve a logarithmic equation, we first use our knowledge of logarithm laws/properties to express the terms in both sides of the equality sign as single terms. Then, we equate the numbers/expressions in the logarithms and hence solve for the unknown variable. Note that the logarithms must be of the same base.
    If one side of the logarithmic equation have logarithm and the other side does not have logarithm, the equation can be easily evaluated by taking the terms in both sides of the equality sign as exponents of powers with the base of the power corresponding to the base of the term having logarithm. The base of the power cancels out the logarithm and then we can evaluate the unknown variable.
    👏SUBSCRIBE to my channel here: czcams.com/users/mrbrianm...
    ❤️Support my channel by becoming a member: / @brianmclogan
    🙋‍♂️Have questions? Ask here: forms.gle/dfR9HbCu6qpWbJdo7
    🎉Follow the Community: / mrbrianmclogan
    Organized Videos:
    ✅Solve Logarithmic Equations
    • Solve Logarithmic Equa...
    ✅Solve Natural Logarithmic Equations
    • Solve Natural Logarith...
    ✅Solve Logarithmic Equations
    • Solve Logarithmic Equa...
    ✅Solve Logarithmic Equations | Learn About
    • Solve Logarithmic Equa...
    ✅Solve Logarithmic Equations with Multiple Logs
    • Solve Logarithmic Equa...
    ✅Solve Logarithmic Equations with Logs on Both Sides
    • Solve Logarithmic Equa...
    🗂️ Organized playlists by classes here: / mrbrianmclogan
    🌐 My Website - www.freemathvideos.com
    🎯Survive Math Class Checklist: Ten Steps to a Better Year: www.brianmclogan.com/email-ca...
    Connect with me:
    ⚡️Facebook - / freemathvideos
    ⚡️Instagram - / brianmclogan
    ⚡️Twitter - / mrbrianmclogan
    ⚡️Linkedin - / brian-mclogan-16b43623
    👨‍🏫 Current Courses on Udemy: www.udemy.com/user/brianmclog...
    👨‍👩‍👧‍👧 About Me: I make short, to-the-point online math tutorials. I struggled with math growing up and have been able to use those experiences to help students improve in math through practical applications and tips. Find more here: www.freemathvideos.com/about-me/
    #Logarithms #logarithmicfunctions #brianmclogan

Komentáře • 54

  • @isabelcamacho-perez676
    @isabelcamacho-perez676 Před 3 lety +69

    thank you for being straightforward, long lectures on math just always goes in one ear and out the other so things like this help a lot

  • @Karbvnyte
    @Karbvnyte Před 4 lety +92

    Headphone users = death by keys

  • @BoZhaoengineering
    @BoZhaoengineering Před 4 lety +4

    By the definition of logarithm, it is directly 2^2 = x^2/(x+3); then this becomes quadratics equation. It ends up with x = 6 and x =-2; You are a great teacher. I wish I had the teacher like you in my high school, explaining everything clearly. Cheers!

  • @Sultan_A
    @Sultan_A Před 3 měsíci +1

    Very Good, Brian McLogan, Keep It Up! 🎉🎉🎉🎉

  • @jaredguerra9324
    @jaredguerra9324 Před 6 lety +17

    great explanation but for some reason im having some trouble with a similar equation where you add the 2 in front of the log aside from this one that multiplies. i have checked everywhere and cant find a clear source. thank you though

  • @milkbread964
    @milkbread964 Před rokem +3

    youve helped me through my 10-week online college math course. thank you 😭🙏 im rewatching these before the final tomorrow

  • @josearielk.repollo8095
    @josearielk.repollo8095 Před 3 lety +4

    Goodmorning sir, could you please make a video about on how to solve logarithmic inequalities? Thank you

  • @RigbyMadewell
    @RigbyMadewell Před 5 lety +4

    Thank you so much

  • @amandanewell5209
    @amandanewell5209 Před 7 měsíci

    you are the BEST! thank you so much for your videos!!

  • @blakeparker6588
    @blakeparker6588 Před 4 lety +2

    thank you so much man

  • @crod1232
    @crod1232 Před 4 lety +5

    Can someone help? Why did you reject the solution x=-2? I know logs can’t take negative inputs, however that 2 out front of the original equation means we would take x^2, therefore the input would always be positive. That’s why I thought it would still be a solution.

    • @crod1232
      @crod1232 Před 4 lety +3

      Also, at 6:16 you said that log2 (6) works, but log2 (9) doesn’t work... why doesn’t that work? Assuming it doesn’t work, then why didn’t you reject the solution x=6?

    • @jdilksjr
      @jdilksjr Před 4 lety +2

      @@crod1232 , he misspoke.

    • @mr.k3108
      @mr.k3108 Před 4 lety

      czcams.com/video/0K5p49E7TWg/video.html

    • @llorell
      @llorell Před 2 lety +2

      @@jdilksjr so when he misspoke, he meant it X=6 does work?

    • @ericlilili5595
      @ericlilili5595 Před rokem +1

      @@crod1232 That will work, he misspoke. You can use the rule and see the negative sign as (x+3)^-1, which I believe will give you the same answer

  • @zay6817
    @zay6817 Před 3 lety +2

    The videos from 2006 are helping

  • @WilliamIngram-fp1mb
    @WilliamIngram-fp1mb Před 6 měsíci +1

    you have saved me brian. god bless.

  • @SuongThol
    @SuongThol Před 3 lety

    goog video,thanks

  • @papahapinesspatrick6371

    Thank you for your tutorial in log but it is not visible at all

  • @mr.knight8967
    @mr.knight8967 Před 3 lety +2

    You are amazing.
    Hope you were my teacher.

  • @saiemullah5953
    @saiemullah5953 Před 3 lety

    I’m doing a question where log2(x+5/x)=3 how would I get my answer from that

  • @lilaroseg
    @lilaroseg Před 4 lety +1

    Shouldn't both be correct? logBase2 of x^2 where x=-2 is logBase2 of 4, minus logBase2(x+3) (which works out to be zero) is equal to 2. For 6, 2logBase2(6)-logBase2(9) will equal two as well.

    • @kaysanmohamed6586
      @kaysanmohamed6586 Před 3 lety

      you can’t evaluate 2log(-2). you have to plug your x value into the original equation

  • @michaelnguyen3159
    @michaelnguyen3159 Před 6 lety +2

    what did you do with the two in log x. Where did it go?

    • @brianmclogan
      @brianmclogan  Před 6 lety +2

      which one? at what point?

    • @3333sweetie
      @3333sweetie Před 5 lety +1

      Why is 6 still an answer if 6 and 3 =9 and that doesn't work?

  • @PintzConsole
    @PintzConsole Před měsícem +1

    Got like 25min before my final 😂

  • @deep6064
    @deep6064 Před 6 lety +2

    Thank U ♥♥♥♥

  • @manuelmolina1467
    @manuelmolina1467 Před 6 lety +2

    Happy anniversary of this video

    • @brianmclogan
      @brianmclogan  Před 6 lety +3

      cheers!

    • @temdb3939
      @temdb3939 Před 3 lety

      @@brianmclogan 4 days away from 9th anniversary, going through most of your log videos for a test tomorrow, you are an absolute lifesaver for putting these on youtube. My math teacher's explanations make me want to blow my brains out. I wish I was in your class, I'd probably get an A+.

  • @user-dh6lc9fz8f
    @user-dh6lc9fz8f Před 8 měsíci

    log5+log(2x+10)-2=log(x-4)

  • @mohammedkhaled2456
    @mohammedkhaled2456 Před 6 lety +3

    Dude -2 in the equation is going to be squared and become positive

    • @brianmclogan
      @brianmclogan  Před 6 lety +1

      what time point?

    • @mohammedkhaled2456
      @mohammedkhaled2456 Před 6 lety +1

      Brian McLogan first of all it turned out that there are two solutions : x =6 and x = -2 ... Near the end of the video you said that if we substituted x = 6 in Log base 2 of ( x + 3 ) it will give us Log base 2 of 9 and it won't work but that's incorrect because Log base 2 of 9 = 3.1699 . Secondly , what I want to understand : why is x = -2 not accepted since 2Log base 2 of x = Log base 2 of (x)^2 = Log base 2 of (-2)^2 = Log base 2 of 4 =2 so why is it unaccepted ?

    • @decoyreggieyt4621
      @decoyreggieyt4621 Před 5 měsíci

      @@mohammedkhaled2456 because it will become and imaginary number

    • @Erlisch1337
      @Erlisch1337 Před 2 měsíci

      @@decoyreggieyt4621 I think they mean if you put the 2 back in so it becomes log2(-2^2)

  • @CrissyAlwaysSunny
    @CrissyAlwaysSunny Před 5 lety

    Why are they torturing us?

  • @Sultan_A
    @Sultan_A Před 3 měsíci +2

    Long 7-Minute Video

  • @mayab218
    @mayab218 Před 2 měsíci

    i think i have adhd

  • @septube26
    @septube26 Před 5 lety

    why don't you ever do the problems I have on my actual homework? I have a equal sign in the middle, separating two logs.

  • @siaiti1026
    @siaiti1026 Před 3 lety

    Thank you so much