已知x＞y,求证:x³－y³＞2x²y－2xy²

已知x+y=2,xy=1/2,求x³y+2x²y²+xy³ x³y-2x²y²+xy³ 已知x/y=2,求2x(x+y)-y(x+y)/4x²-4xy+y² 化简x-y分之x + x³-2x²y+xy²分之y³ ÷ y²-x&# 2x+y=0,求4x²+2xy(x+y)+y³ 因式分解x的5次方y-x³y+2x²y-xy 多项式因式分解 1,(x-y)³-(x-y)²(x+y) 2,x(x²-xy)-(4x&# 先化简,再求值:{xy(x²-3y)+3xy²}(-2xy)+x³y²(2x-y 因式分解：xy³－2x²y²＋x³y [-xy/(x-y)²]²×(y²-xy/x)³ 已知2x+y+4,xy=2,求-4x²y²-y³x-4x³y的值 已知：x+y=5,x²+y² =11,求代数式x³y-2x²y²+xy