(x+y)(x²-xy+y²)+3xy=x²-xy+y²+3xy 这个怎么变得?
计算:(xy-x²)×x-y/xy
x²/xy-x/y
3x²y+xy²-[2xy²-4x²y+(x²y-2xy²)
已知x:y=3:2,求(x²+3xy)/(xy+2xy)
x-y/x²÷x²-2xy+y²/xy*(xy-x²)
计算 2xy[4x²y²-3y(xy+x²y)-xy²]
[-xy/(x-y)²]²×(y²-xy/x)³
已知x/y=3,求(x²+2xy-3xy²)/(x²-xy+y²)
计算:(xy-x²)乘 x-y分之xy
x/xy-y²与y/x²-xy 通分
求3x²y-2xy²+2(xy-二分之三x²y)-xy+3xy²的值,其中x=3
3x²-xy-4xy²-3x+4y=0怎么做