Answer
$(y^2+6)(2y^2-1)$
Work Step by Step
The 2 numbers whose product is $ac=
2(-6)=-12
$ and whose sum is $b=
11
$ are $\{
12,-1
.\}$ Using these two numbers to decompose the middle term of the given expression, $
2y^4+11y^2-6
,$ then the factored form is
\begin{array}{l}\require{cancel}
2y^4+12y^2-1y^2-6
\\\\=
(2y^4+12y^2)-(y^2+6)
\\\\=
2y^2(y^2+6)-(y^2+6)
\\\\=
(y^2+6)(2y^2-1)
.\end{array}
