а) $$10\sqrt{3}-4\sqrt{48}-\sqrt{75}=10\sqrt{3}-4\sqrt{16\cdot3}-\sqrt{25\cdot3}=10\sqrt{3}-4\cdot4\sqrt{3}-5\sqrt{3}=10\sqrt{3}-16\sqrt{3}-5\sqrt{3}=-11\sqrt{3}$$
б) $$(3-\sqrt{2})^2=3^2-2\cdot3\cdot\sqrt{2}+(\sqrt{2})^2=9-6\sqrt{2}+2=11-6\sqrt{2}$$
Ответ: а) $$-11\sqrt{3}$$; б) $$11-6\sqrt{2}$$