Answer
$3\sqrt{2x}$
Work Step by Step
Simplify each radical to obtain
$\sqrt{25(2x)} - \sqrt{4(2x)}
\\=\sqrt{5^2(2x)}-\sqrt{2^2(2x)}
\\=5\sqrt{2x}-2\sqrt{2x}.$
RECALL:
The distributive property states that for any real numbers a, b, and c,
$(ac-bc)=(a-b)c.$
Use the rule above to obtain
$(5-2)\sqrt{2x}
\\=3\sqrt{2x}.$