Answer
$\frac{1}{-125}$
Work Step by Step
We want to simplify: $(-5)^{-3}$
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 $\frac{1}{(-5)^3}$.
Next, we must simplify the power in the denominator: $\frac{1}{(-5)\times(-5)\times(-5)}=\frac{1}{-125}$