Answer
$\frac{\sqrt {15}}{3}$
Work Step by Step
$\frac{\sqrt {5x}}{\sqrt {3x}}=\frac{\sqrt {5}\times\sqrt x}{\sqrt {3}\times\sqrt x}=\frac{\sqrt {5}}{\sqrt {3}}=\frac{\sqrt {5}\times\sqrt 3}{\sqrt {3}\times\sqrt 3}=\frac{\sqrt {5\times3}}{\sqrt {3\times3}}=\frac{\sqrt {15}}{\sqrt {9}}=\frac{\sqrt {15}}{3}$