How do you simplify 5 square root of 8 times square root 18?

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Answer 1 · 2015-07-19T12:21:59

Use $sqrt(ab) = sqrt(a)sqrt(b)$ (for $a, b >= 0$ ) to find:

$5sqrt(8)sqrt(18) = 60$

If $a, b >= 0$ then $sqrt(ab) = sqrt(a)sqrt(b)$

So:

$5sqrt(8)sqrt(18) = 5sqrt(8*18) = 5sqrt(144) = 5sqrt(12^2) = 5*12 = 60$

Answer 2 · 2015-07-19T12:25:08

Try and get the squares out of the root

$5*sqrt8*sqrt18=5*sqrt(8*18)$

Since $8=2^3and18=2*3^2$

$=5*sqrt(2^3*2*3^2)=5*sqrt(2^4*3^2)$

$=5*sqrt((2^2)^2)*sqrt(3^2)=5*2^2*3=60$