a) [tex](1+\sqrt{2})^{2} + (1-\sqrt{2})^{2} = 1+2\sqrt{2}+2 + 1-2\sqrt{2}+2 = 6[/tex]
b) [tex](\sqrt{3} - 1)^{2} - (2-\sqrt{3})^{2} = 3-2\sqrt{3}+1 - (4-4\sqrt{3}+3) = 4 - 2\sqrt{3} - 4 + 4\sqrt{3} - 3 = 2\sqrt{3} - 3[/tex]
