推导公式:(x+y)(x²-xy+y²)=x³+y³

[-xy/(x-y)²]²×(y²-xy/x)³ 2x+y=0,求4x²+2xy(x+y)+y³ -x³y³-x²y²+xy x³y-2x²y²+xy³ x²/xy-x/y 已知x+y=2,xy=1/2,求x³y+2x²y²+xy³ 化简x-y分之x + x³-2x²y+xy²分之y³ ÷ y²-x&# [x（x²y²-xy）-y（x²-x³y）]÷3x²y 【x(x²y²-xy)-y(x²-x³y)】÷3x²y 因式分解：[x（x²y²-xy）-y（x²-x³y）]÷3x²y 已知x+y=5,xy=3,x³+y³=(x+y)(x²-xy+y²),则1/x& 一.x-y=2,则x²-2xy+y²= 二.x-y=-1,xy=3,则x³y-2x