Answer
$4\sqrt{2}$
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:
$=\sqrt{25(2)}-\sqrt{2}
\\=\sqrt{5^2(2)} - \sqrt{2}
\\=5\sqrt2 -\sqrt2$
RECALL:
For any real numbers $a, b,$ and $c$,
$ac-bc=(a-b)c$
Use the rule above to combine like terms:
$=(5-1)\sqrt{2}
\\=4\sqrt{2}$