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Math Help - Solve for x using logs

  1. #1
    Newbie mushufasa11's Avatar
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    Solve for x using logs

    I am getting very frustrated with this problem as it seems no matter what happens the x's cancel out.


    If anyone could help me solve this I would greatly appreciate it.
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  2. #2
    Grand Panjandrum
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    Quote Originally Posted by mushufasa11 View Post
    I am getting very frustrated with this problem as it seems no matter what happens the x's cancel out.



    If anyone could help me solve this I would greatly appreciate it.
    Take natural logs:

    ln(2) + 3x = ln(4) + 5x

    rearrange:

    2x = ln(2) - ln(4) = ln(2/4) = ln(1/2)

    so:

    x=(1/2) ln(1/2) = ln(1/sqrt(2)).

    RonL
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  3. #3
    Newbie mushufasa11's Avatar
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    Thanks a lot man.

    This is what I was doing before when taking the natural logs.

    (3x)(ln2) = (5x)(ln4)

    Leaving it as a product, rather than adding. I guess I didnt understand the property lne^x = x.

    thanks again
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