问题描述: (x+y)(x-y)-(2x+y)(x-y+1)计算要过程 1个回答 分类:数学 2014-11-06 问题解答: 我来补答 (x+y)(x-y)-(2x+y)(x-y+1)=x^2-y^2-(2x^2-2xy+2x+xy-y^2+y)=x^2-y^2-2x^2+2xy-2x-xy+y^2-y=-x^2+xy-2x-y如果不懂,祝学习愉快! 展开全文阅读