121（x-y)＾2－169(x+y)＾2

1、x(x-y)(x+y)-x(x+y)^2 (1)(x^2/x)-y-x-y 【(x-y)^2+(x+y)(x-y)】除以 2x 先化简再求植:0.5(x+y+2)＾+0.5(x-y-2)(x-y+2)-2(x+y)其中x-y=6,xy=21 [(-x-y)(-x+y)-(x+y)^2-x(y-y^2)}÷1/2y x^2-y^2/x+y-4x(x-y)+y^2/2x-y, (x+y)^2(x-y)^2-(x-y)(x+y)(x^2+y^2)分解因式 化简:(x-3y)(x+y)-(x-2y)(x+2y)-(x-y)平方 【x-3y][x+y]-[x-2y][x +2y]-[x-y [(3x+y)(x-y)-(2x+3y)(x-y)]*(x-y) 有这样一道题:"计算(2*x*x*x-3*x*x*y-2*x*y*y)-(x*x*x-2*x*y*y+y*y*y)+【- [x(x-y)-y(x-y)+(x+y)(x-y)]÷2x其中x=2012 y=2013