Answer
$4a^{7}b^{6}$
Work Step by Step
Using $\dfrac{a^x}{a^y}=a^{x-y}$, then the expression, $
\dfrac{8a^9b^7}{2a^2b}
$, simplifies to
\begin{array}{l}\require{cancel}
\dfrac{\cancel{2}\cdot4a^{9-2}b^{7-1}}{\cancel{2}}
\\\\=
4a^{7}b^{6}
.\end{array}