## Thinking Mathematically (6th Edition)

$\\=\underline{5}\sqrt2+\underline{4}\sqrt2 \\=\underline{9\sqrt2}$
We use the properties of radicals that we know to simplify. $\sqrt{25}\cdot \sqrt2 + \sqrt{16} \cdot \sqrt2 \\=5\sqrt2+4\sqrt2 \\=9\sqrt2$