#### Answer

$15\sqrt{3}$

#### Work Step by Step

Simplify the radicals that can still be simplified by factoring the radicand so that one of the factors is a perfect square:
$=5\sqrt{4(3)}+\sqrt{25(3)}
\\=5\sqrt{2^2(3)} +\sqrt{5^2(3)}
\\=5\cdot 2\sqrt{3} + 5\sqrt{3}
\\=10\sqrt{3}+5\sqrt{3}$
RECALL:
For any real numbers $a, b,$ and $c$,
$ac+bc=(a+b)c$
Use the rule above to combine like terms:
$=(10+5)\sqrt{3}
\\=15\sqrt{3}$