(3x+2y)(3x-2y)-(x-3y)(3x+y) 2(2x-1)(2x+1)-5x(-x+3y)+4x(-4x^2

（x+2)(x+3) (x-4)(x+1) (y+4)(y-2) (y-5)(y-3) x/x-y*y^2/x+y-x^3y2/x^4-y^4/x^2/x^2+y^2 {3(x+y)-4(x-y)=4 {x+y/2 + x-y/6=1 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x=1/3,y=-1/2,求代数式x-(x+y)+(x+2y)-(x+3y)+(x+4y)-(x+5y)+...-( (x+3y-4)(2x-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)+【- 化简[(3x+4y)^2-(2x+y)(2x-y)+(-x+y)(5x-y)]除以-2y,其中x=-1,y=1 数学(x-y)^5*(y-x)^3*(x-y)^2 1、x(x-y)(x+y)-x(x+y)^2 若2x-3y+4=0则x（x*x-1)+x(5-x*x)-6y+7 化简:(x-3y)(x+y)-(x-2y)(x+2y)-(x-y)平方