a) (√5-√3)²= (√5)²-2√5*√3+(√3)²= 5-2V15+3
b) 3/√b= 3/√b *√b/√b= 3√b/√b*√b = 3√b/b
c) 4/(√7-√3)= 4/(√7-√3) * (√7+√3)/√7+√3) =
4(√7+√3) / (√7-√3)(√7+√3) = 4(√7+√3)/(7-3) = 4(√7+√3) / 4= √7+√3
d) 1/(2-√3)= 1/(2-√3) * (2+√3)/( 2+√3)= (2+√3)/(2-3)= (2+√3)/-1=
= -(2+√3)= -2-√3
e)3/(V5+V2)= 3/(V5+V2) *(V5-V2)/(V5-V2)= 3(V5-V2)/(5-2)=
= 3(V5-2) /3=V5-2
f)(V5)^2 /V10= 5/V10* V10/V10 = 5V10/10= 1/5 V10