Question

What is the following product 3 sqrt 2(5 sqrt 6-7 sqrt 3)

Answer 1

$3\sqrt2\cdot(5\sqrt6-7\sqrt3)=3\cdot5\cdot\sqrt{2\cdot6}-3\cdot7\cdot\sqrt{2\cdot3}\\\\=15\sqrt{12}-21\sqrt6=15\sqrt{4\cdot3}-21\sqrt6=15\cdot\sqrt4\cdot\sqrt3-21\sqrt6\\\\=15\cdot2\cdot\sqrt3-21\sqrt6=\boxed{30\sqrt3-21\sqrt6}$
$Used:\\\sqrt{a}\cdot\sqrt{b}=\sqrt{a\cdot b}$

Answer 2

The answer is C. !!!!