（x+3y)²-2（x-y)（x+y)+(x+y)²其x=0.5,y=-2

已知X-Y/X+Y=3,求代数式2(x-y)/X+Y-3X+Y/X+Y 已知x-y/x+y=3,求代数式5(x-y)/x+y-x+y/2(x-y) 已知x/y=2,求2x(x+y)-y(x+y)/4x²-4xy+y² [x(x-y)-y(x-y)+(x+y)(x-y)]÷2x其中x=2012 y=2013 【2(x-y)^3-8(x-y)^2(x+y)+6y(x-y)^2】/2(x-y)^2= 已知x,y的值满足方程组x+2y=3,x-y=-2,求x/(x-y)²+x²-y²/(x+ 化简后求值 [(x-2y)²+(x-2y)(x-2y)-2x(2x-y)]÷2x 其中x=2 y=3 先化简再求值(x-y)(x+y)-(x-2y) 的完全平方+x(3x-5y)-(x-y)(x-2y),其中x=1/2 y 已知x²+y²+5=2x+4y,求【2x²-(x-y)(x-y)】【(x+y-1)(x-y (2x-y)²-4(x-y)(x+2y) 化简：（2x-y)²-4(x-y)(x+y) 若x、y满足2x+y=6,x-3y=1,求7y(x-3y)²-2(3y-x)³的值