已知正实数x y满足x-根号xy-2y=0求 x+3根号xy+2y/2x-2根号下xy-y

答：x>0,y>0x-√(xy)-2y=0(√x-2√y)(√x+√y)=0因为：x>0,y>0所以：√x+√y>0所以：√x-2√y=0所以：√x=2√y所以：x=4y所以：[ x+3√(xy)+2y ] / [2x-2√(xy)-y ]=(4y+3*2y+2y) / (8y-2*2y-y)=12y / (3y)=4...