Question

Simplify the radical expression 5√7+2√175

Answer 1

$5\sqrt{7} + 2\sqrt{175}=5\sqrt{7}+2\sqrt{25 \cdot 7}=5\sqrt{7}+ 2 \cdot \sqrt{25} \cdot \sqrt{7}= \\ \\ = 5\sqrt{7}+2 \cdot 5 \cdot \sqrt{7}=5\sqrt{7}+10\sqrt{7}=\boxed{15\sqrt{7}} \approx 39.69$

remember about formula $\sqrt{ab} = \sqrt{a} \cdot \sqrt{b}$