Answer
$30x^{4}y-54x^2y^{2}$
Work Step by Step
Using the Distributive Property, the product of the given expression, $
6x^2y(5x^2-9y)
,$ is
\begin{array}{l}\require{cancel}
6x^2y(5x^2)+6x^2y(-9y)
\\\\=
30x^{2+2}y-54x^2y^{1+1}
\\\\=
30x^{4}y-54x^2y^{2}
.\end{array}