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Logarithms homework question

  1. Nov 19, 2008 #1
    1. The problem statement, all variables and given/known data
    12^x=4X8^(2x)

    Big X= multiplication sign
    little x= unknown

    i simply cannot figure this out. Any help please?

    2. Relevant equations
    4.6X1.06^(2x+3)=5X3^(x)
     
  2. jcsd
  3. Nov 19, 2008 #2

    Dick

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    Re: logarithms!

    Use logarithms! Isn't that your title? Take the log of both sides and use the rules of logarithms to simplify. What do you get?
     
  4. Nov 19, 2008 #3
    Re: logarithms!

    i wouldnt post this if i could do it as easily as you said. Can you explain? Thats why i'm here.
     
  5. Nov 19, 2008 #4

    Dick

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    Re: logarithms!

    log(12^x)=log(4*8^(2x)). That wasn't so hard. Now simplify it. Use rules of logarithms like, log(a*b)=log(a)+log(b), log(a^b)=b*log(a).
     
  6. Nov 19, 2008 #5

    HallsofIvy

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    Re: logarithms!

    Your equation is 12x=(4)82x.

    Since you titled this "logarithms", Dick assumed you knew some basic rules of logarithms. Take the logarithm of both sides: log(12x= log((4)82x)

    Now use the fact that log(ab)= log(a)+ log(b) and that log(ax)= x log(a).
     
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