Answer
$x^3-4x^2y+4xy^2-y^3$
Work Step by Step
Using the Distributive Property, the product of the given expression, $
(x-y)(x^2-3xy+y^2)
,$ is
\begin{array}{l}\require{cancel}
x(x^2)+x(-3xy)+x(y^2)-y(x^2)-y(-3xy)-y(y^2)
\\\\=
x^3-3x^2y+xy^2-x^2y+3xy^2-y^3
\\\\=
x^3+(-3x^2y-x^2y)+(xy^2+3xy^2)-y^3
\\\\=
x^3-4x^2y+4xy^2-y^3
.\end{array}
