#### Answer

$(7xy)^{1/2}$

#### Work Step by Step

Using the definition of rational exponents which is given by $a^{\frac{m}{n}}=\sqrt[n]{a^m}=\left(\sqrt[n]{a}\right)^m,$ the expression above is equivalent to
\begin{array}{l}\require{cancel}
\sqrt{7xy}
\\\\=
\sqrt[2]{7xy}
\\\\=
(7xy)^{1/2}
.\end{array}