How do you simplify sqrt 90 times sqrt 40 - sqrt 8 times sqrt 1890×408×18?

2 Answers
Apr 22, 2017

color(blue)4848

Explanation:

sqrt90 xx sqrt40-sqrt8 xx sqrt1890×408×18

:.=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

Apr 22, 2017

60-12 =48

Explanation:

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