How do you simplify 4√5 - 2√45?
1 Answer
Oct 9, 2015
Explanation:
Your starting expression looks like this
#4sqrt(5) - 2sqrt(45)#
Notice that you can write
#45 = 3 * 15 = 3 * 3 * 5 = 3^2 * 5#
This means that you have
#4sqrt(5) - 2sqrt(3^2 * 5) = 4sqrt(5) - 2 * sqrt(3^2) * sqrt(5)#
#=4sqrt(5) - 2 * 3sqrt(5)#
#= 4sqrt(5) - 6sqrt(5)#
#= sqrt(5) * (4 - 6)#
#= color(green)(-2sqrt(5))#
