化简1— x-y/x+2y÷x²-y²/x²+4xy+4y²

来源：学生作业学帮网编辑：学帮网时间：2024/05/30 11:36:23

原式=1-(x-y)/(x+2y)*(x+2y)²/(x+y)(x-y)
=1-(x+2y)/(x+y)
=(x+y-x-2y)/(x+y)
=-y/(x+y)