Answer
$-3x^2(6x^2-3x-2)$
Work Step by Step
Factoring the negative $GCF=
-3x^2
,$ the given expression, $
-18x^4+9x^3+6x^2
,$ is equivalent to
\begin{array}{l}\require{cancel}
-3x^2
\left(
\dfrac{-18x^4}{-3x^2}+\dfrac{9x^3}{-3x^2}+\dfrac{6x^2}{-3x^2}
\right)
\\\\=
-3x^2(6x^2-3x-2)
.\end{array}