Answer
$\sqrt{7x}$
Work Step by Step
Simplify each radical to obtain
$\sqrt{9(7x)} - \sqrt{4(7x)}
\\=\sqrt{3^2(7x)}-\sqrt{2^2(7x)}
\\=3\sqrt{7x}-2\sqrt{7x}.$
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
$(3-2)\sqrt{7x}
\\=1\cdot \sqrt{7x}
\\=\sqrt{7x}$
