Answer
$-\frac{4}{9}$
Work Step by Step
According to the negative exponent rule, $a^{-n}=\frac{1}{a^{n}}$.
Therefore, $-3^{-1}-9^{-1}=-(3^{-1}+9^{-1})=-(\frac{1}{3}+\frac{1}{9})=-(\frac{1\times3}{3\times3}+\frac{1}{9})=-(\frac{3+1}{9})=-(\frac{3+1}{9})=-\frac{4}{9}$.
