Упростите выражение: a) $$5\sqrt{75} + \sqrt{2}(\sqrt{8} - \sqrt{24})$$; б) $$(\sqrt{8}-\sqrt{5})^2$$.

a) $$5\sqrt{75} + \sqrt{2}(\sqrt{8} - \sqrt{24}) = 5\sqrt{25\cdot3} + \sqrt{2}(\sqrt{4\cdot2} - \sqrt{4\cdot6}) = 5\cdot5\sqrt{3} + \sqrt{2}(2\sqrt{2} - 2\sqrt{6}) = 25\sqrt{3} + 2\sqrt{2\cdot2} - 2\sqrt{2\cdot6} = 25\sqrt{3} + 2\cdot2 - 2\sqrt{12} = 25\sqrt{3} + 4 - 2\sqrt{4\cdot3} = 25\sqrt{3} + 4 - 2\cdot2\sqrt{3} = 25\sqrt{3} + 4 - 4\sqrt{3} = 21\sqrt{3} + 4$$. б) $$(\sqrt{8}-\sqrt{5})^2 = (\sqrt{8})^2 - 2\sqrt{8}\sqrt{5} + (\sqrt{5})^2 = 8 - 2\sqrt{40} + 5 = 13 - 2\sqrt{4\cdot10} = 13 - 2\cdot2\sqrt{10} = 13 - 4\sqrt{10}$$. Ответ: a) $$21\sqrt{3} + 4$$; б) $$13 - 4\sqrt{10}$$