What is #-sqrt(20) + 3 sqrt(45)#?
1 Answer
Jan 22, 2017
Explanation:
-
Factor the numbers under each square root and look for "perfect square" factors
#-sqrt(color(red)((4)(5))) + 3sqrt(color(red)((9)(5)))# -
Separate the terms in the square roots
#-color(red)(sqrt(4)sqrt(5))+3color(red)(sqrt(9)sqrt(5))# -
Simplify the roots (
#sqrt(4)=2# and#sqrt(9)=3# )
#-color(red)(2)sqrt(5)+3color(red)((3))sqrt(5)# -
Simplify
#-2sqrt(5)+color(red)(9)sqrt(5)# -
Combine terms
#7sqrt(5)#