2x+2y-x+y=3;x+y-2x+2y=1 方程组的解

x-y/x-x+y/y-(x+y)(x-y)/y² y/x=2 x(x-y)2-(y-x)3 (x-y) (x-2y)+(x+2y) (x-3y)-2(x-3y) (x-4y)= (x+y)(x-y)+(x-y)平方-(x-y)(3x-y) 其中x=-2 y=3分之一 已知x-y/x+y=3,求代数式5(x-y)/x+y-x+y/2(x-y) [2/3x-2/x+y(x+y/3x-x-y)]/x-y/x 化简：{2/3x-2/(x+y)[(x+y)/3x-x-y]}/(x+y)/x 计算2/3x-2/x+y(x+y/3x-x-y)/x-y/x 化简3x-2/(x+y)[(x+y)/3x-x-y]÷(x-y)/x (x+y)(2x-3y)=? 化简y(x+y)+(x+y)(x-y)-x^2 因式分解x(x+y)(x-y)-x(x+y)^2 (x+y)(x-y)-(x-y)^2如题 (x+y)(x-y)-(x-y)^2 计算：x+2y/x-y+2x/y-x-3y/x-y 化简:(x-3y)(x+y)-(x-2y)(x+2y)-(x-y)平方 [(3x+y)(x-y)-(2x+3y)(x-y)]*(x-y) 【2(x-y)^3-8(x-y)^2(x+y)+6y(x-y)^2】/2(x-y)^2= 【2(x-y)(x-y)(x-y)-8(x-y)(x-y)(x+y)+6y(x-y)(x-y)]/2(x-y)(x-y)