Ответ:\(8\sqrt3-5\sqrt{12}+4\sqrt{75}=8\sqrt3-10\sqrt3+20\sqrt3=18\sqrt3\).\(\frac{\sqrt{20}+\sqrt{80}}{\sqrt5}=\frac{2\sqrt5+4\sqrt5}{\sqrt5}=6\).Ответ: 1) \(18\sqrt3\); 2) 6.