[tex]\displaystyle \\
\sqrt{5^3\times a^5\times b^2} = \\ \\
=\sqrt{5^2\times 5 \times a^4\times a \times b^2} = \\ \\
=\sqrt{5^2 \times a^4 \times b^2 \times 5 \times a } = \text{(Scoatem patratele de sub radical)}\\ \\
=\boxed{5a^2b\sqrt{ 5a }}[/tex]
