Answer
$-27x^{11}y^{15}$
Work Step by Step
Using the laws of exponents, the given expression, $
(-3xy)^3(-x^2y^3)^4
,$ simplifies to
\begin{array}{l}\require{cancel}
(-3)^3x^{1(3)}y^{1(3)}\cdot (-1)^4x^{2(4)}y^{3(4)}
\\\\=
-27x^{3}y^{3}\cdot (1)x^{8}y^{12}
\\\\=
-27(1)x^{3+8}y^{3+12}
\\\\=
-27x^{11}y^{15}
.\end{array}
