## Elementary Algebra

$-36x^3\sqrt{2x}$
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.