Answer
$\dfrac{-64p^{15}}{27m^{6}n^{9}}$
Work Step by Step
Using $\left(\dfrac{a}{b}\right)^x=\dfrac{a^x}{b^x}$, then the expression, $
\left(\dfrac{-4p^5}{3m^2n^3}\right)^3
$, simplifies to
\begin{array}{l}\require{cancel}
\dfrac{(-4p^5)^3}{(3m^2n^3)^3}
.\end{array}
Using $(a^x)^y=a^{xy}$, then the given expression, $
\dfrac{(-4p^5)^3}{(3m^2n^3)^3}
$, simplifies to
\begin{array}{l}\require{cancel}
\dfrac{(-4)^3p^{5(3)}}{3^3m^{2(3)}n^{3(3)}}
\\\\=
\dfrac{-64p^{15}}{27m^{6}n^{9}}
.\end{array}
