Answer
$\dfrac{a^{35}}{b^{10}}$
Work Step by Step
Using the laws of exponents, the given expression, $
(a^{-7}b^2)^{-5}
,$ simplifies to
\begin{array}{l}\require{cancel}
a^{-7(-5)}b^{2(-5)}
\\\\=
a^{35}b^{-10}
\\\\=
\dfrac{a^{35}}{b^{10}}
.\end{array}