Answer
$-\dfrac{16p^{7}}{q}$
Work Step by Step
Using the laws of exponents, the given expression, $
(8p^2q^3)(-2p^5q^{-4})
,$ simplifies to
\begin{array}{l}\require{cancel}
8(-2)p^{2+5}q^{3+(-4)}
\\\\=
-16p^{7}q^{-1}
\\\\=
\dfrac{-16p^{7}}{q^1}
\\\\=
-\dfrac{16p^{7}}{q}
.\end{array}
