Answer
$5x^2\sqrt{x}$
Work Step by Step
Getting the perfect factors and then extracting its root, the simplified form of the given expression, $
\sqrt{25x^{5}}
,$ is
\begin{array}{l}\require{cancel}
\sqrt{25x^{4}\cdot x}
\\\\=
\sqrt{(5x^2)^2\cdot x}
\\\\=
5x^2\sqrt{x}
.\end{array}
Note that variables are assumed to represent positive real numbers.