a)
(2\sqrt{10}-\sqrt3)(4\sqrt{10}+3\sqrt3)=8*10+6\sqrt{30}-4\sqrt{30}-3*3=71+2\sqrt{30}
b)
(2\sqrt7+4\sqrt5)(\sqrt5+3\sqrt7)=2\sqrt{35}+6*7+4*5+12\sqrt{35}=62+14\sqrt{35}
c)
(\sqrt{11}-2\sqrt2)(3\sqrt{11}-4\sqrt2)=3*11-4\sqrt{22}-6\sqrt{22}+8*2=49-10\sqrt{22}
d)
(2\sqrt5-\sqrt2)(4\sqrt2+3\sqrt5)=8\sqrt{10}+6(\sqrt5)^2-4*(\sqrt2)^2-3\sqrt{10}=
5\sqrt{10}+6*5-4*2=11\sqrt{10}+22
=11(\sqrt{10}+2)