Chapter 7 - Section 7.4 - Adding, Subtracting, and Multiplying Radical Expressions - Exercise Set - Page 439: 52

$y\sqrt{5}+5\sqrt{y}$

Using the Distributive Property and the properties of radicals, then, \begin{array}{l} \sqrt{5y}\left( \sqrt{y}+\sqrt{5} \right) \\= \sqrt{5y^2}+\sqrt{25y} \\= \sqrt{y^2\cdot5}+\sqrt{25\cdot y} \\= y\sqrt{5}+5\sqrt{y} .\end{array}