Answer
$\pm\frac{1}{5}$
Work Step by Step
Rewrite in exponential form.
$x^{-2}=5^2$
Raise each side to the $-\frac{1}{2}$ power. $(x^{-2})^{-1(\frac{1}{2})}=x$. First take the square root.
$x^{-1}=\pm5$
Then raise to the negative first power.
$x=\pm\frac{1}{5}$