化简 2x-[3y-5x-(-2x-7y)]等于 （ ） A：-7x+10y B：5x+4y C:-x-4y D:9x-10y

化简:3(x-y)²-7(x-y)+ 2(x-y)²+5(x-y) 化简3(x-y)-7(x--y)+2(y-x) 化简:5(x-y)+2(x+y)-3(x-y) 化简：{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 化简:(x-3y)(x+y)-(x-2y)(x+2y)-(x-y)平方 化简：[(x+2y)^2-(x+y)(3x-y)-5y^2]/2x 化简y(x+y)+(x+y)(x-y)-x^2 计算(x^8-x^7y+x^5y^3-x^4y^4+x^3y^5-x^y^7+y^8)(x^2+xy+y^2) 整体去括号；化简[5(x-y)-3(x-y)-(x-y)+2(x-y)]-2(x-y) 整体去括号；[5(x-y)-3(x-y)-(x-y)+2(x-y)]-2(x-y)化简 把(x-y)看作一个整体,化简:(1)5(x-y)+2(x-y)-4(x-y);(2)3(x-y²-4(x-y)+7（x-y)-6(x-y) 已知x-y/x+y=3,求代数式5(x-y)/x+y-x+y/2(x-y) 化简(X-2Y)-(Y-3X) 化简[(3x+4y)^2-(2x+y)(2x-y)+(-x+y)(5x-y)]除以-2y,其中x=-1,y=1 (2x-3y)-(5x-y) (2X-3y)-(5x-y) (2x-5y)(3x+y)