已知x^2+y^2-2x-4y+5=0,求1/xy+1/(x+1)(y+1)+1/(x+2)(y+2)+……1/(x+2
已知x+y=-1,xy=-2,求代数式-5(x+y)+(x-y)+x(xy+y)的值
已知实数x,y满足x²+y²-xy+2x-y+1=0 求x y
已知x+y=-1,xy=-2,求代数式-5(x+y)+(x-y)+2(xy+y)的值
已知X+Y=-1,xy=-2,求代数式-5(x+y)+(x-y)+(xy+y)的值
已知4x=9y求(1)x+y/y (2)y-x/2x
已知x^2+y^2+x^2y^2-4xy+1=0 求(x-y)^2008-(xy)^2008
已知X²+Y²+X²Y²-4XY+1=0 求:(X-Y)^2008-(XY)^2
已知x-y=3,xy=1,求(-2x+2x+3y)-(3xy+2y-2x)-(x+4y+xy)
x+y=1,xy=-1/2,求x(x+y)(x-y)-x(x+y)2
已知5x^2-4xy+y^2+y-2x+1=0,求(x-y)^2005
已知:x-y=1,xy=-2.求:(-2xy+2x+3y)-(3xy+2y-2x)-(x+4y+xy)的值
.已知:x-y=1,xy=-2.求:(-2xy+2 x+3y)-(3xy+2y-2x)-(x+4y+xy)的值