b: \(=4\sqrt{2}-2\sqrt{6}+4\sqrt{3}-6-4\sqrt{3}+2\sqrt{6}-4\sqrt{2}\)
=-6
d: \(=8-2\sqrt{15}+2\sqrt{15}=8\)
\(b,=4\sqrt{2}+4\sqrt{3}-2\sqrt{6}-6-4\sqrt{3}+2\sqrt{6}-4\sqrt{2}=-6\\ d,=5-2\sqrt{15}+3+2\sqrt{15}=8\\ f,=3-4\sqrt{15}+20-4\left(3+2\sqrt{15}+5\right)=23-4\sqrt{15}-32-8\sqrt{15}=-9-12\sqrt{15}\)
`b)`\(\left(\sqrt{2}+\sqrt{3}\right)\left(4-2\sqrt{3}\right)-2\left(2\sqrt{3}-\sqrt{6}\right)-4\sqrt{2}\)
\(=4\sqrt{2}-2\sqrt{6}+4\sqrt{3}-6-4\sqrt{3}+2\sqrt{6}-4\sqrt{2}\)
\(=-6\)
`d)`\(\left(\sqrt{5}-\sqrt{3}\right)^2+2\sqrt{15}\)
\(=5+3-2\sqrt{15}+2\sqrt{15}\)
`=8`
`f)`\(\left(\sqrt{3}-2\sqrt{5}\right)^2-4\left(\sqrt{3}+\sqrt{5}\right)^2\)
\(=3+20-4\sqrt{15}-4\left(8+2\sqrt{15}\right)\)
\(=23-4\sqrt{15}-32-8\sqrt{15}\)
\(=-9-12\sqrt{15}\)

