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Math Help - Exponential Function

  1. #1
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    Exponential Function

    If 13^{-x}=10, what does 13^{2x} equal?

    Answer is:
    13^{2x}=\frac{1}{100}

    How do you solve this?

    <br />
\frac{log 13}{log x} = 10<br />

    Is that the right start?
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  2. #2
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    Some progress..

    <br />
\frac{13}{13x}=10<br />

    <br />
13=10(13^x)<br />

    <br />
13=130^x<br />

    <br />
\frac{13}{130}=x<br />

    <br />
\frac{1}{10}=x<br />
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  3. #3
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    Quote Originally Posted by desiderius1 View Post
    If 13^{-x}=10, what does 13^{2x} equal?

    Answer is:
    13^{2x}=\frac{1}{100}

    How do you solve this?

    <br />
\frac{log 13}{log x} = 10<br />

    Is that the right start?
    13^{-x}=10 \Rightarrow 13^x = \frac{1}{10} \Rightarrow (13^x)^2 \frac{1}{100} ....
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