Помогите решить!!!!! 1.)√4x+√64x-√81x=? 2.)(5√7-√63+√14)*√7=? 3.)√12y-0,5√48y+2√108y=?

Решите задачу:

$1) \sqrt{4x} +\sqrt{64x}-\sqrt{81x}=2\sqrt{x}+8\sqrt{x}-9\sqrt{x}=\sqrt{x} \\ \\ 2)(5\sqrt{7}-\sqrt{63}+\sqrt{14})*\sqrt{7}=(5\sqrt{7}-3\sqrt{7}+\sqrt{14})*\sqrt{7}= \\ =(2\sqrt{7}+\sqrt{2*7})*\sqrt{7}=2*7+\sqrt{2*7*7} =14+7 \sqrt{2} \\ \\ 3) \sqrt{12y}-0.5\sqrt{48y}+2\sqrt{108y}= \sqrt{4*3y}-0.5\sqrt{16*3y}+2\sqrt{36*3y}= \\ =2\sqrt{3y}-0.5*4\sqrt{3y}+2*6\sqrt{3y}=2\sqrt{3y}-2\sqrt{3y}+12\sqrt{3y}= \\ =12\sqrt{3y}$