Answer
$3x^3$
Work Step by Step
The $GCF$ of $
-3
$ and $
6
$ is $
3
.$
The $GCF$ of $
x^4
$ and $
x^3
$ is $
x^3
.$
Hence, the $GCF$ of the given expressions, $
-3x^4
\text{ and } 6x^3
,$ is
\begin{array}{l}\require{cancel}
3x^3
.\end{array}