若xy=1,x+y=2,求1/4x^2-1/2xy+1/4y^2的值

若x-y=4,xy=1,求(-2xy+2x+3y)-(3xy+2y-2x)-(x+4y+xy)的值 已知：x-y=1,xy=-2.求：(-2xy+2x+3y)-(3xy+2y-2x)-(x+4y+xy)的值 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 若1/x-1/y=3,求5x+2xy-5y/x-4xy-y的值 已知1/x-1/y=4,求2x+xy-2y/x-2xy-y的值 已知1/x-1/y=3,求(3x+4xy-3y)/(x-2xy-y)的值 已知1/x+1/y=3,求3x-4xy+3y/(x+2xy+y)的值 若x,y满足x^+2y^-2xy+1=0,求xy的值 已知x+y=-1,xy=-2,求代数式-5（x+y)+(x-y)+x(xy+y)的值 已知|3-y|＋|x+y|=0,求[2(x+y)-3(xy+4)]÷1／xy的值. 若1/x-1/y=3 求 2x-3xy-2y/x-2xy-y的值