(3x²-xy-2y²)-2(x²+xy-2y²)化简
x-y/x²÷x²-2xy+y²/xy*(xy-x²)
3x²y+xy²-[2xy²-4x²y+(x²y-2xy²)
化简(3X²-XY+Y²)-5(X²-XY+2Y²)
计算 2xy[4x²y²-3y(xy+x²y)-xy²]
化简(X²+2XY+Y²)(X²—XY+Y²)²
-2y³+(3xy²-x²y)-2(xy²-y³)
计算:(-7x²y)(2x²y-3xy³+xy)
计算;(xy-x²)÷x²-2xy+y²/xy · x-y/x²
(xy-x²)除以xy分之x²-2xy+y²乘以x²分之x-y
化简3/(x²+2xy+y²)-4/(x²-2xy+y²)+5/(x²
化简4xy-3y²-3x²+xy-3xy-2x²+x²-2y²
求3x²y-2xy²+2(xy-二分之三x²y)-xy+3xy²的值,其中x=3