Solve the exponential equation: $64=0.8^d \cdot100$ I tried doing: $64/100=80/100^d$ but since there is no common factor which gives these numbers with different powers I failed to find the value of variable $d$. How to solve it then?

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    $\begingroup$ If you think of it as $64/100=(8/10)^d$ the answer will be clear. $\endgroup$ Jul 8, 2015 at 22:58
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    $\begingroup$ You could always be "dumb" and simply use: $a^x = b \rightarrow x = \frac{\log(b)}{\log(a)}$ (I'm guessing you're supposed to do this without a calculator though). $\endgroup$
    – Jared
    Jul 8, 2015 at 23:04

1 Answer 1


$$64/100 = .64$$

So then you have $.8^d = .64$

What does $.8 \times .8$ equal?


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