已知：y=根号（x-8)+根号（8-x)+18 求(根号x-根号y)分之(x+y) 减去 x倍的根号y减去y倍的根号x分之2xy

∵X-8≥0,8-X≥0,∴X=8,∴y=0+0+18=18,∴(x+y)/(√x-√y)-2xy/(x√y-y√x)=(x+y)/(√x-√y)-2xy/[(√(xy)(√x-√y)]=(x+y)/(√x-√y)-2√(xy)/(√x-√y)=(x-2√xy+y)/(√x-√y)=(√x-√y)²/(√x-√y)=√x-√y=...