9) -6q^-2 11) (1)/(x^-2) 13) -(2x)/(a^-4) 15) (a^-1)/(b^-1)

9) $-6q^{-2}$<br /><br />To simplify this expression, we can rewrite it as $-6 \cdot \frac{1}{q^2}$. This means that the expression is equal to $-\frac{6}{q^2}$.<br /><br />11) $\frac {1}{x^{-2}}$<br /><br />To simplify this expression, we can rewrite it as $x^2$. This means that the expression is equal to $x^2$.<br /><br />13) $-\frac {2x}{a^{-4}}$<br /><br />To simplify this expression, we can rewrite it as $-2x \cdot a^4$. This means that the expression is equal to $-2x \cdot a^4$.<br /><br />15) $\frac {a^{-1}}{b^{-1}}$<br /><br />To simplify this expression, we can rewrite it as $\frac{1}{a} \cdot \frac{1}{b}$. This means that the expression is equal to $\frac{1}{ab}$.