Answer
$\dfrac{9\sqrt{14}}{14}$
Work Step by Step
Rationalize each denominator to obtain:
\begin{align*}
&=\frac{\sqrt{2}}{\sqrt7}\cdot \frac{\sqrt7}{\sqrt7}+\frac{\sqrt{7}}{\sqrt2}\cdot \frac{\sqrt2}{\sqrt2}\\\\
&=\frac{\sqrt{14}}{7}+\frac{\sqrt{14}}{2}
\end{align*}
Make the expressions similar using their LCD which is $14$ to obtain:
\begin{align*}
&=\frac{\sqrt{14} \cdot 2}{7\cdot 2}+\frac{\sqrt{14}\cdot 7}{2\cdot 7}\\\\
&=\frac{2\sqrt{14}}{14}+\frac{7\sqrt{14}}{14}\\\\
&=\frac{(2+7)\sqrt{14}}{14}\\\\
&=\frac{9\sqrt{14}}{14}
\end{align*}
