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Math Help - Logarithm questions

  1. #1
    Junior Member
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    Logarithm questions

    Here are a couple of questions:

    First:

    You are given the equation y=logbase 10 (kx-4) + c
    The x intercept is (7,0) and the graph passes through the points (52,1).
    Determine the value of k and c.


    Second:

    Solve for A in terms of B and C if:
    A, B, and C > 1, and
    logbase C (AB) - 1/logbase A (C) = logbase C (A) + logbase root12 (12)

    Any help is appreciated.
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  2. #2
    Super Member
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    Quote Originally Posted by Shapeshift View Post
    Here are a couple of questions:

    First:

    You are given the equation y=logbase 10 (kx-4) + c
    The x intercept is (7,0) and the graph passes through the points (52,1).
    Determine the value of k and c.

     y = \log_{10}{kx-4}+C . The x intercept is (7,0). Hence:

     0 = \log_{10}{7k-4}+C

     \log_{10}{7k-4}=-C

     7k-4=10^{-C}

    The other point gives:


     1 = \log_{10}{52k-4}+C

    \log_{10}{52k-4}=1-C

    \log_{10}{52k-4}=1-C

    52k-4=10^{1-C}

    You now have two equations and two unknowns (C and k), can you solve them?


    Second:

    Solve for A in terms of B and C if:
    A, B, and C > 1, and
    logbase C (AB) - 1/logbase A (C) = logbase C (A) + logbase root12 (12)

    Any help is appreciated.

    \log_{C}{|AB|} - \frac{1}{\log_{A}{|C|} = log_{C}{|A|} + log_{\sqrt{12}}{|12|}
    Mush
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