Answer
$\sqrt{42} -\sqrt{70}$
Work Step by Step
RECALL:
(i) For non-negative real numbers $a$ and $b$,
$\sqrt{a} \cdot \sqrt{b} = \sqrt{ab}$
(ii) For all real numbers $a, b,$ and $c$,
$a(b-c) = ab-ac$
Use rule (ii) above to obtain:
$=\sqrt{7} \cdot \sqrt{6} -\sqrt{7} \cdot \sqrt{10}$
Use rule (i) above to obtain:
$=\sqrt{42} -\sqrt{70}$
