#### Answer

$x\sqrt{5} + \sqrt{15}$

#### Work Step by Step

RECALL:
(1) Distributive Property:
For any real numbers a, b, and c,
$a(b+c) = ab+ ac$
(2) For any real numbers real numbers a and b within the domain,
$\sqrt[n]{a} \cdot \sqrt[n]{b} = \sqrt[n]{ab}$
Use rule (1) above to obtain:
$=\sqrt{5} \cdot x + \sqrt{5} \cdot \sqrt{3}
\\=x\sqrt{5} + \sqrt{5} \cdot \sqrt{3}$
Use rule (2) above to obtain:
$=x\sqrt{5} + \sqrt{5 \cdot 3}
\\=x\sqrt{5} + \sqrt{15}$