Question

Найдите значение выражения

Answer 1

$10 \sqrt{7} \times 2 \sqrt{6} \times \sqrt{42} = 10 \times 2 \times \sqrt{7} \times \sqrt{6} \times \sqrt{42} = 20 \times \sqrt{42} \times \sqrt{42} = \\ \\ = 20 \times {( \sqrt{42}) }^{2} = 20 \times 42 = 840$