Answer
$-\frac{5}{24}$
Work Step by Step
According to the negative exponent rule, $a^{-n}=\frac{1}{a^{n}}$.
Therefore, $8^{-1}-3^{-1}=\frac{1}{8}-\frac{1}{3}=\frac{1\times3}{8\times3}-\frac{1\times8}{3\times8}=\frac{3-8}{24}=\frac{-5}{24}=-\frac{5}{24}$.
