(-2xy^2)^2·3x^2·y÷(-x^3y^4)
化简:x-y/x+3y÷x^-y^2/x^2+6xy+9y^2-(xy/x+y)
[-(x-y)^2/xy]^-4*(y^2-xy/x)^3*(x^4/y^10)÷(xy-y^2/x)^-5=-y(y-
3x²y+xy²-[2xy²-4x²y+(x²y-2xy²)
(2x-y)(2x+y)+(2x-y)(y-4x)+2y(y-3x)+2x^4y^2÷(xy)^2
计算;(xy-x²)÷x²-2xy+y²/xy · x-y/x²
(x-2xy)*(-xy+2y*y)-(3x*x-2xy)(x-9xy+6y*y)
已知x-y=-2/3,求(x·x+y.y)的完全平方-4xy(x·x+y·y)+4x·x·y·y的值
计算:3xy[2xy-x(y-2)+x]
(-3x^y+2xy)-( )=4x^+xy
计算4xy+(x-2y)的平方+(x+3y)(3y-x)
先化简,再求值:3xy²(-x²y+2x³y²)-4xy(-xy²)·
利用x-y=3^2009,xy=-3^2010,求代数式:(2x+3y-2xy)-(x+4y+xy)-(3xy+2y-2