#### Answer

$-\frac{1}{27}$

#### Work Step by Step

Recall the rule: $x^{-n}=\frac{1}{x^{n}}$
We first rearrange the expression into a form that doesn't contain any negative exponents, and then we solve the expression.
$(-3)^{-3}=\frac{1}{(-3)^{3}}=\frac{1}{-3\times -3\times -3}=\frac{1}{-27}=-\frac{1}{27}$