Answer
$\color{blue}{\dfrac{4}{a^2}}$
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) $a^m \cdot a^n = a^{m+n}$
(7) $a^0=1, a\ne0$
Use rule (5) above to obtain:
$=\dfrac{4a^5(a^{-1\cdot3})}{a^{-2\cdot(-2)}}
\\=\dfrac{4a^5\cdot a^{-3}}{a^4}$
Use rule (6) above to obtain:
$=\dfrac{4a^{5+(-3)}}{a^4}
\\=\dfrac{4a^2}{a^4}$
Use rule (2) above to obtain:
$=4a^{2-4}
\\=4a^{-2}$
Use rule (1) above to obtain:
$=4 \cdot \dfrac{1}{a^2}
\\=\color{blue}{\dfrac{4}{a^2}}$
