已知x+y=2xy,且xy不等于0,则求-2x+6xy-2y/(7x+5y)-9xy-(3x+y)=___

问题描述:

已知x+y=2xy,且xy不等于0,则求-2x+6xy-2y/(7x+5y)-9xy-(3x+y)=___

-2x+6xy-2y/(7x+5y)-9xy-(3x+y)
=[3(x+y)-x-y]/[7x+5y-9/2(x+y)-3x-y]
=2(x+y)/[-1/2(x+y)]
=-4