Answer
$-\frac{1}{25}$
Work Step by Step
We want to simplify: $-5^{-2}$
The negative exponent rule states that for every nonzero number $a$ and integer $n$, $a^{-n}=\frac{1}{a^n}$.
We use this to rewrite the expression as $-\frac{1}{5^2}$.
Next, we must simplify the power on the denominator: $-\frac{1}{5\times5}=-\frac{1}{25}$