Answer
$10xy\sqrt[]{3}$
Work Step by Step
Using the properties of radicals, the given expression, $
5\sqrt[]{12x^2y^2}
,$ simplifies to
\begin{array}{l}\require{cancel}
5\sqrt[]{4x^2y^2\cdot3}
\\\\=
5\sqrt[]{(2xy)^2\cdot3}
\\\\=
5\cdot2xy\sqrt[]{3}
\\\\=
10xy\sqrt[]{3}
.\end{array}
Note that all of the variables are assumed to represent non-negative real numbers.