# How do you simplify -18a^2b^-3?

The only part which can be simplified is the index of $b$
Recall: ${x}^{-} m - \frac{1}{x} ^ m$
$- 18 {a}^{2} {b}^{-} 3$
=$- \frac{18 {a}^{2}}{b} ^ 3$