3.(√5+3)(√5+2)
=√5(√5+2)+3(√5+2)
=5+2√5+3√5+6
=11+5√5
4(√a+√b)(3√a-√b)
=√a(3√a-√b)+√b(3√a-√b)
=3a-√ab+3√ab-b
=3a-b+2√a