Answer
$\dfrac{y}{7\sqrt{y}}$
Work Step by Step
Rationalizing the numerator of $
\dfrac{\sqrt{y}}{7}
$ results to
\begin{array}{l}
\dfrac{\sqrt{y}}{7}
\cdot
\dfrac{\sqrt{y}}{\sqrt{y}}
\\\\=
\dfrac{\sqrt{y^2}}{7\sqrt{y}}
\\\\=
\dfrac{y}{7\sqrt{y}}
.\end{array}