怎样化简:2x²-2y²+3xy-5y²+x²
化简求值:x-y/x²-2xy+y²-xy+y²/x²-y²,其中(x
怎样因式分解5x²+6xy-8y²-3x+8y-2
化简求值3x²y-[2xy-2(xy-3/2x²y)+xy]+3xy²其中x=3、y=-1
化简求值[1-(2x/x+y)]÷ (x²-2xy+y²/3x+3y)+(x²+xy/x&
(xy-2y)(xy+2y)-(x-y)²-x²y² 其中x=5/2 y=- 3/5 先化
x-y/x²÷x²-2xy+y²/xy*(xy-x²)
化简(3X²-XY+Y²)-5(X²-XY+2Y²)
急![(3x+y)²-3(3x-y)(x+y)-(x-3y)(x+3y)]÷(2xy)
计算3x[xy-2x(1/y-x/3]+3y(x²-y²)
3x²y+xy²-[2xy²-4x²y+(x²y-2xy²)
(2x²y-3xy²)-3(x²y-2xy²)+2(x²y-4xy
1/x+1/y=5,求2x-3xy+2y/x²+xy+y的值