Question 456568
sqrt( 15 )- sqrt ( 3/5 )
=sqrt(15)-sqrt(3)/sqrt(5)
=(sqrt(75)-sqrt(3))/sqrt(5)
=(5sqrt(3)-sqrt(3))/sqrt(5)
=4sqrt(3)/sqrt(5)
=4sqrt(3)/sqrt(5) * sqrt(5)/sqrt(5)
=4sqrt(15)/5
.
Ed