化简 x²-3xy+y²
化简4xy-3y²-3x²+xy-3xy-2x²+x²-2y²
化简-3x²y+2x²y+3xy²-2xy²
化简(3X²-XY+Y²)-5(X²-XY+2Y²)
计算:(xy-x²)×x-y/xy
x²/xy-x/y
化简3/(x²+2xy+y²)-4/(x²-2xy+y²)+5/(x²
3x²y+xy²-[2xy²-4x²y+(x²y-2xy²)
(2x²y-3xy²)-3(x²y-2xy²)+2(x²y-4xy
(3xy)² · (x²+xy-y²)-3xy(3x³y+3x²y
先化简,再求值:{xy(x²-3y)+3xy²}(-2xy)+x³y²(2x-y
化简2XY+(X-Y)²
化简:[(x+y)²-(x-y)²]÷2xy