How do you simplify sqrt84 * sqrt28?

1 Answer
Apr 30, 2016

sqrt(84)*sqrt(28)=sqrt(28^2*3)=28sqrt(3)

Explanation:

Here's a factor tree for 28:

color(white)(0000)28
color(white)(000)"/"color(white)(00)"\"
color(white)(00)2color(white)(000)14
color(white)(00000)"/"color(white)(00)"\"
color(white)(0000)2color(white)(0000)7

So: 28 = 2^2*7

color(white)()
Here's a factor tree for 84:

color(white)(0000)84
color(white)(000)"/"color(white)(00)"\"
color(white)(00)2color(white)(000)42
color(white)(00000)"/"color(white)(00)"\"
color(white)(0000)2color(white)(000)21
color(white)(0000000)"/"color(white)(00)"\"
color(white)(000000)3color(white)(0000)7

So: 84 = 2^2*3*7 = 28*3

color(white)()
So:

sqrt(84)*sqrt(28)=sqrt(84*28)=sqrt(28^2*3)=28sqrt(3)