Answer
$y^2(3-x)(9+3x+x^2)$
Work Step by Step
Factoring the $GCF=
y^2
$ results to $
y^2(27-x^3)
$. Using $a^3+b^3=(a+b)(a^2-ab+b^2)$, or the factoring of the sum/difference of two cubes, then,
\begin{array}{l}
y^2(27-x^3)
\\=
y^2[3+(-x)][(3)^2-(3)(-x)+(-x)^2)
\\=
y^2(3-x)(9+3x+x^2)
.\end{array}
