Answer
$\dfrac{2\sqrt{15}}{21}$
Work Step by Step
Rationalizing the denominator of the given expression, $
\dfrac{2\sqrt{5}}{7\sqrt{3}}
,$ we find:
\begin{array}{l}\require{cancel}
\dfrac{2\sqrt{5}}{7\sqrt{3}}\cdot\dfrac{\sqrt{3}}{\sqrt{3}}
\\\\=
\dfrac{2\sqrt{15}}{7\sqrt{(3)^2}}
\\\\=
\dfrac{2\sqrt{15}}{7\cdot3}
\\\\=
\dfrac{2\sqrt{15}}{21}
.\end{array}