计算：(21x^4y^3+35x^3y^2+7x^2y^2)÷7x^2y

计算(21x^4y^3-35x^3y^2+7x^2y^2)/(-7x^2y) 计算 3x+4y/x-y+3y/y-x-4x/x-y 计算（2x-3y)(x+4y)-(3x+y)(x-2y)（2x-3y)(x+4y)-(3x+y)(x-2y) (x-3y)(y+2x)-(4y-3x)(3x+4y)计算 计算:(x-y)^2*(x+y)^3*(-x-y)^3*(y-x)^4 计算 x(x-3y) 计算:(x+3y)(2x-y) 计算:(2x-3y)(x+y) 计算:(-x-2y) * (3x-y) 计算：(x+y)-3(x-2y). 计算2/3x-2/x+y(x+y/3x-x-y)/x-y/x 计算：(x+3y)(x-3y)-(x-3y) 计算(x+y)(x+y)^2(-x-y)^3 3x(x-y)+2y(x-y) 计算 计算3x/(x-3y)+(x+y)/(4y-x)-7y/(x-4y)=? 计算：x+2y/x-y+2x/y-x-3y/x-y 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) 计算:[(2x - 3y)^2 - (x-y)(4x+2y)] / 2y