Answer
$4(3y^2+4y-2)$
Work Step by Step
Factoring the $GCF=
4
,$ the given expression, $
12y^2+16y-8
,$ is equivalent to
\begin{array}{l}\require{cancel}
4
\left(
\dfrac{12y^2}{4}+\dfrac{16y}{4}-\dfrac{8}{4}
\right)
\\\\=
4(3y^2+4y-2)
.\end{array}