✨ 最佳解答 ✨ 祐人 約10年以前 x(x+1)(x+2)-y(y+1)(y+2)+xy(x-y) =x³+3x²+2x-y³-3y²-2y+xy(x-y) =x³-y³+3(x²-y²)+2(x-y)+xy(x-y) =(x-y)(x²+xy+y²)+3(x+y)(x-y) +2(x-y)+xy(x-y) =(x-y){(x²+xy+y²)+3(x+y)+2+xy} =(x-y){x²+2xy+y²+3(x+y)+2} =(x-y){(x+y)²+3(x+y)+2} =(x-y)(x+y+1)(x+y+2) まっぴい 約10年以前 ありがとうございます! 留言
ありがとうございます!