College Algebra 7th Edition

$9\sqrt{3}$
Factor each radicand so that one of the factors is a perfect square to obtain: $=\sqrt{25(3)} + \sqrt{16(3)} \\=\sqrt{5^2(3)}+\sqrt{4^2(3)}$ Simplify each radical to obtain: $=5\sqrt{3} + 4\sqrt{3}$ Combine like radicals to obtain: $=(5+4)\sqrt{3} \\=9\sqrt{3}$