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How do you solve for x in #9^x=1/81#?

1 Answer

KillerBunny · mason m

Dec 4, 2015

#x=-2#

Explanation:

First of all, observe that #9^2=81#. Then, remember how negative powers work:

#a^{-b} = 1/a^{b}#.

So, we have that #1/81 = 1/9^2 = 9^{-2}#.

Now, we know that #9^x=9^(-2)#.

And so #x=-2#.

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