Answer
$-36x^3\sqrt{2x}$
Work Step by Step
Using the properties of radicals, the given expression, $
-6\sqrt{72x^7}
,$ simplifies to
\begin{array}{l}\require{cancel}
-6\sqrt{36x^6\cdot2x}
\\\\=
-6\sqrt{(6x^3)^2\cdot2x}
\\\\=
-6\cdot6x^3\sqrt{2x}
\\\\=
-36x^3\sqrt{2x}
.\end{array}
Note that all of the variables are assumed to represent non-negative real numbers.
