3x²y-[x²y²-2(xy-2/3x²y)+xy]+3x²y
计算3x[xy-2x(1/y-x/3]+3y(x²-y²)
急![(3x+y)²-3(3x-y)(x+y)-(x-3y)(x+3y)]÷(2xy)
3x²y+xy²-[2xy²-4x²y+(x²y-2xy²)
(2x²y-3xy²)-3(x²y-2xy²)+2(x²y-4xy
先化简,再求值:{xy(x²-3y)+3xy²}(-2xy)+x³y²(2x-y
若x=1/2,y=1 求x(x²+xy+y²)-y(x²+xy+y²)+3xy(
下列多项式:(1)x²+xy-y²;(2)-x²+2xy-y²;(3)xy+x&
1/x+1/y=5,求2x-3xy+2y/x²+xy+y的值
x²/xy-x/y
一.x-y=2,则x²-2xy+y²= 二.x-y=-1,xy=3,则x³y-2x
(x+3y)(x-y)-(x+y)^2 =x²-xy+3xy-3y²-x²-y²
化简求值3x²y-[2xy-2(xy-3/2x²y)+xy]+3xy²其中x=3、y=-1