Question

Simplify:$\sqrt{42(42-20)(42-30)(42-34)}$

Answer 1

$=\sqrt{42\times 22\times 12\times 4}$

$=\sqrt{2\times 3\times 7\times 2\times 11\times 2\times 2}$

$=2\times 2\sqrt{3\times 7\times 11}$

$=4\sqrt{231}$