(-2xy^2)(3x^2y)^2
计算:3xy[2xy-x(y-2)+x]
xy(xy+1)+(xy+3)-2(x+y+2分之一)-(x+y-1)的平方
(x-2xy)*(-xy+2y*y)-(3x*x-2xy)(x-9xy+6y*y)
化简!1、(x^2-xy)+xy+y^2 2、3(x^2-xy)-xy+y^2
(xy-x^2)乘以(xy)/(x-y)
(x+2y-3xy)-(-2x-y+xy),其中x+y=,xy=-,求值.
3x²y+xy²-[2xy²-4x²y+(x²y-2xy²)
x-y/x²÷x²-2xy+y²/xy*(xy-x²)
x^2-xy-6y^2+3xy+y+2
利用x-y=3^2009,xy=-3^2010,求代数式:(2x+3y-2xy)-(x+4y+xy)-(3xy+2y-2
计算 2xy[4x²y²-3y(xy+x²y)-xy²]
计算3xy[2xy-x(y-2)+x-1]