How do you simplify $- 5 \sqrt{21} \cdot - 3 \sqrt{42}$ $-5sqrt21*-3sqrt42$ ?

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Answer 1 · 2015-04-10T11:40:49

You can write your product as:
$[- 5 \sqrt{7 \cdot 3}] \cdot [- 3 \sqrt{7 \cdot 6}] =$ $[-5sqrt(7*3)]*[-3sqrt(7*6)]=$

$= [- 5 \sqrt{7} \sqrt{3}] \cdot [- 3 \sqrt{7} \sqrt{6}] =$ $=[-5sqrt(7)sqrt(3)]*[-3sqrt(7)sqrt(6)]=$

$= [- 5 \sqrt{7} \sqrt{3}] \cdot [- 3 \sqrt{7} \sqrt{3} \sqrt{2}] =$ $=[-5sqrt(7)sqrt(3)]*[-3sqrt(7)sqrt(3)sqrt(2)]=$

Multiplying:

$= 15 \cdot 7 \cdot 3 \cdot \sqrt{2} = 315 \sqrt{2}$ $=15*7*3*sqrt(2)=315sqrt(2)$

How do you simplify -5sqrt21*-3sqrt42−5√21⋅−3√42-5sqrt21*-3sqrt42?