Answer
$22\sqrt2$
Work Step by Step
$5\sqrt8+2\sqrt{72}\longrightarrow$ factor the perfect squares out of 8 and 72
=$5\sqrt{4\times2}+2\sqrt{36\times2}\longrightarrow$ multiplication property of square roots
=$5(\sqrt{4})(\sqrt2)+2(\sqrt{36})(\sqrt2)\longrightarrow$ simplify
=$5(2)(\sqrt2)+2(6)(\sqrt2)\longrightarrow$ multiply
=$10\sqrt2+12\sqrt2\longrightarrow$ use distributive property
=$\sqrt2(10+12)\longrightarrow$ simplify
=$22\sqrt2$
