#### Answer

$-x(x^2+9)(x^2-2)$

#### Work Step by Step

Factoring the $GCF=
x
,$ the given expression is equivalent to
\begin{array}{l}\require{cancel}
-(x^5+7x^3-18x)
\\\\=
-x(x^4+7x^2-18)
.\end{array}
Using the factoring of trinomials in the form $x^2+bx+c,$ the $\text{
expression
}$
\begin{array}{l}\require{cancel}
(x^4+7x^2-18)
\end{array} has $c=
-18
$ and $b=
7
.$
The two numbers with a product of $c$ and a sum of $b$ are $\left\{
9,-2
\right\}.$ Using these two numbers, the $\text{
expression
}$ above is equivalent to
\begin{array}{l}\require{cancel}
-x(x^2+9)(x^2-2)
.\end{array}