【数学】化简2mn(3x²y-2xy²)-xy²+2x²y
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4xy-3y²-3x²+xy-3xy-2x²+x²-2y²
计算:x²+2xy+y²/xy-y².x²-2xy+y²/xy+y
化简(X²+2XY+Y²)(X²—XY+Y²)²
化简-3x²y+2x²y+3xy²-2xy²
-2y³+(3xy²-x²y)-2(xy²-y³)
(2x²y-3xy²)-3(x²y-2xy²)+2(x²y-4xy
数学:先化简再求值(x²+xy-2y²/x²-2xy+y²)-(1-xy
计算:(-7x²y)(2x²y-3xy³+xy)