Chapter 7 - Section 7.5 - Rationalizing Denominators and Numerators of Radical Expressions - Exercise Set - Page 445: 66

$\dfrac{y}{7\sqrt{y}}$

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}