Answer
$\sqrt \frac{14}{xy}$
Work Step by Step
The product rule holds that $\sqrt[n] a\times\sqrt[n] b=\sqrt[n] (ab)$ (where $\sqrt[n] a$ and $\sqrt[n] b$ are real numbers).
Therefore, $\sqrt \frac{7}{x}\times\sqrt \frac{2}{y}=\sqrt (\frac{7}{x}\times\frac{2}{y})=\sqrt \frac{14}{xy}$
