Answer
$x+y$.
Work Step by Step
The given expression is
$=\frac{x^3y-y^3x}{x^2y-xy^2}$
Factor out $xy$ from the numerator and denominator.
$=\frac{xy(x^2-y^2)}{xy(x-y)}$
Factor $x^2-y^2$.
Use the algebraic identity $a^2-b^2=(a+b)(a-b)$.
$=(x+y)(x-y)$.
Substitute the factor.
$=\frac{xy(x+y)(x-y)}{xy(x-y)}$
Cancel common terms.
$=x+y$.
