(﹣2xy²)×(3x²y)²
x-y/x²÷x²-2xy+y²/xy*(xy-x²)
3x²y+xy²-[2xy²-4x²y+(x²y-2xy²)
计算 2xy[4x²y²-3y(xy+x²y)-xy²]
-2y³+(3xy²-x²y)-2(xy²-y³)
化简(3X²-XY+Y²)-5(X²-XY+2Y²)
计算:(-7x²y)(2x²y-3xy³+xy)
求3x²y-2xy²+2(xy-二分之三x²y)-xy+3xy²的值,其中x=3
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
(1)-2分之1xy(3y²-2xy+3x²y)
(1/2x²y-2xy+y²)×3xy
计算:x²y-(2xy²-5x²y)+3xy²-y³