Answer
$(x-y)(x^2+xy+y^2)$
Work Step by Step
Using $a^3+b^3=(a+b)(a^2-ab+b^2)$ or the factoring of 2 cubes, the factored form of the given expression, $
x^3-y^3
,$ is
\begin{array}{l}
(x-y)[(x)^2-(x)(-y)+(-y)^2]
\\\\=
(x-y)(x^2+xy+y^2)
.\end{array}