Answer
$\color{blue}{-4r^6}$
Work Step by Step
RECALL:
(1) $a^{-m} = \dfrac{1}{a^m}$
(2) $\dfrac{a^m}{a^n} = a^{m-n}$
(3) $\left(\dfrac{a}{b}\right)^m=\dfrac{a^m}{b^m}$
(4) $(ab)^m = a^mb^m$
(5) $(a^m)^n=a^{mn}$
(6) $a^m \cdot a^n = a^{m+n}$
Use rule (5) above to obtain:
$=-4r^{-2}r^{4\cdot 2}
\\=-4r^{-2}r^8$
Use rule (6) above to obtain:
$=-4r^{-2+8}
\\=\color{blue}{-4r^6}$
