\(a.\left(2-\sqrt{3}+\sqrt{5}\right)\left(2-\sqrt{5}+\sqrt{3}\right)\)
\(=4-\left(\sqrt{3}-\sqrt{5}\right)^2\)
\(=4-3+2\sqrt{15}-5\)
\(=2\sqrt{15}-4\)
\(b.2\sqrt{3}\left(\sqrt{3}-3\right)-\left(3\sqrt{3}-1\right)^2\)
\(=6-6\sqrt{3}-27+6\sqrt{3}-1\)
\(=-22\)