Answer
$x=-3$
Work Step by Step
If $b\gt0$ and $b\ne1$, then $y=log_{b}x$ means $x=b^{y}$ for every $x$ and every real number $y$.
Therefore, $log_{5}\frac{1}{125}=x$ is equivalent to $5^{x}=\frac{1}{125}$.
We know that $x=-3$, because $5^{-3}=\frac{1}{5^{3}}=\frac{1}{125}$.
