How do you simplify Square root of 63 - Square root of 28?

2 Answers
Mar 3, 2018

#\sqrt{63}-\sqrt{28}=\sqrt{3^2*7}-\sqrt{2^2*7}=3\sqrt{7}-2\sqrt{7}=\sqrt{7}#

Mar 3, 2018

Answer:

#sqrt(7) #

Explanation:

We must use our surd knowledge:

#sqrt(a*b)= sqrt(a)*sqrt(b) #

#=> sqrt(63) = sqrt(9 * 7 ) = sqrt(9)*sqrt(7) = 3sqrt(7) #

#=> sqrt(28) = sqrt(4*7) = sqrt(4)*sqrt(7) = 2sqrt(7) #

#therefore sqrt(63) - sqrt(28) -= 3sqrt(7) - 2sqrt(7) #

#= sqrt(7) #