-3x²+6x²y-3xy²

3x-2xy-8-2x+6xy-x²+6、-x²+2xy-y²-3x²-2xy+ 已知x/y=2,求x²-xy+3y²/x²+xy+6y²的值 x²/xy-x/y (x-y)²-(3x-3xy+y²)因式分解 计算：(xy-x²)×x-y/xy 3x²y+xy²-[2xy²-4x²y+（x²y-2xy²） (2x²y-3xy²)-3(x²y-2xy²)+2（x²y-4xy&# (3xy)² · (x²+xy-y²)-3xy(3x³y+3x²y&# 化简 (x+y)(x²-xy+y²) ； 3（2x-1）(x+6)-5(x-3)(x+6) 先化简,再求值:{xy(x²-3y)+3xy²}(-2xy)+x³y²(2x-y 计算3x/8y×16y²/27x² （2xy-x²）÷x-2y/xy 2x-6/x A=2x²-3xy+y²-x+2y,B=4x²-6xy+2y²+3x-y,若x=