How do you simplify $sqrt 90 times sqrt 40 - sqrt 8 times sqrt 18$ ?

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Answer 1 · 2017-04-22T15:00:00

$color(blue)48$

$sqrt90 xx sqrt40-sqrt8 xx sqrt18$

$:.=sqrt(3*3*10) xx sqrt(2*2*10)-sqrt(2*2*2) xx sqrt(3*3*2)$

$:.sqrt3*sqrt3=3,sqrt2*sqrt2=2$

$:.=3sqrt10 xx 2sqrt10-2sqrt2 xx 3sqrt2$

$:.=6 xx 10-6 xx 2$

$:.color(blue)(60-12=48$

Answer 2 · 2017-04-22T19:54:26

$60-12 =48$

If you are multiplying the same roots you can combine them into one root:

Here we are multiplying square roots:

$sqrta xx sqrt b = sqrt(axxb)$

$sqrt90 xxsqrt40 - sqrt8 xxsqrt18$

In this case they multiply to give perfect squares:

$=sqrt3600 - sqrt144" "larr$ find the roots

$= 60 - 12$

$=48$

How do you simplify sqrt 90 times sqrt 40 - sqrt 8 times sqrt 18sqrt 90 times sqrt 40 - sqrt 8 times sqrt 18?