Precalculus: Mathematics for Calculus, 7th Edition

a) We have ($\frac{2}{3}$)$^{-2}$= $\frac{1}{(\frac{2}{3})^{2}}$= $\frac{1}{(\frac{4}{9})}$ = $\frac{9}{4}$ b) (-5)$^{4}$= (-5) $\times$ (-5) $\times$ (-5) $\times$(-5) = 25 $\times$ 25 = 625 However, -5$^{4}$= -(5$^{4}$) = -625