3(x²-y²)-1/2(xy-y)²化简
计算3x[xy-2x(1/y-x/3]+3y(x²-y²)
化简-3x²y+2x²y+3xy²-2xy²
化简(3X²-XY+Y²)-5(X²-XY+2Y²)
若x=1/2,y=1 求x(x²+xy+y²)-y(x²+xy+y²)+3xy(
化简4xy-3y²-3x²+xy-3xy-2x²+x²-2y²
下列多项式:(1)x²+xy-y²;(2)-x²+2xy-y²;(3)xy+x&
化简:[(x+y)²-(x-y)²]÷2xy
1/x+1/y=5,求2x-3xy+2y/x²+xy+y的值
化简求值3x²y-[2xy-2(xy-3/2x²y)+xy]+3xy²其中x=3、y=-1
化简(x²y-4y²)/(x²+4xy+4y²)*[(4xy)/(x-2y)+x
3x²y+xy²-[2xy²-4x²y+(x²y-2xy²)
(2x²y-3xy²)-3(x²y-2xy²)+2(x²y-4xy