Answer
$\color{blue}{\dfrac{4n^7}{3m^7}}$
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) $(ab)^m = a^mb^m$
Divide the coefficients together by canceling common factors, then use rule (2) above to simplify the variables to obtain:
$\require{cancel}=\dfrac{\cancel{16}4}{\cancel{12}3}m^{-5-2}n^{4-(-3)}
\\=\dfrac{4}{3}m^{-7}n^{4+3}
\\=\dfrac{4}{3}m^{-7}n^7$
Use rule (1) above to obtain:
$=\dfrac{4}{3} \cdot \dfrac{1}{m^7} \cdot n^7
\\=\color{blue}{\dfrac{4n^7}{3m^7}}$