化简-(3x²-3xy)+2(-2xy+2x²)
化简(3X²-XY+Y²)-5(X²-XY+2Y²)
x-y/x²÷x²-2xy+y²/xy*(xy-x²)
3x²y+xy²-[2xy²-4x²y+(x²y-2xy²)
-3(2x²-xy)+4(x²+xy-6)
化简!1、(x^2-xy)+xy+y^2 2、3(x^2-xy)-xy+y^2
计算:3xy[2xy-x(y-2)+x]
求3x²y-2xy²+2(xy-二分之三x²y)-xy+3xy²的值,其中x=3
计算 2xy[4x²y²-3y(xy+x²y)-xy²]
化简3/(x²+2xy+y²)-4/(x²-2xy+y²)+5/(x²
计算:(-7x²y)(2x²y-3xy³+xy)
化简:xy分之3x^2+2xy-xy分之2x^2-xy=
化简4xy-3y²-3x²+xy-3xy-2x²+x²-2y²