1.(x+2y)(2x-y)

1.[(x-y)^2-2(y -x)]÷(x-y) 1.(x-2y)(x+2y)-(x平方+y)(x平方-y) 2.(2x-y)(y+2x)-(2y+x)(2y-x) 1、x(x-y)(x+y)-x(x+y)^2 1.（（y+2x)(-2x+y)+4(x+2y)^2)/3y 2.（2(x-y)^3-8(x-y）^2(x+y)+6y( (1)(x^2/x)-y-x-y 先化简 再求值(x-2y)(2y-x)+(2x+y)(2x-y )-(x-2y)(2x+y) 其中x=-2,y=-1. 【(x-y)^2+(x+y)(x-y)】除以 2x 1.（x+y-z)+(x-y+z)-(x-y-z) 2.2x-(3x-2y+3)-(5y-2) [(-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