_________________________________________________________________

　　_________________________________________________________________

　　_________________________________________________________________

　　_________________________________________________________________

　　_________________________________________________________________

　　13. (***)已知直线l过点P(3,1)且被两条平行直线l1：x＋y＋1＝0，l2：x＋y＋6＝0截得的线段长为5，求直线l的方程．

　　_________________________________________________________________

　　_________________________________________________________________

　　_________________________________________________________________

　　_________________________________________________________________

　　_________________________________________________________________

　　_________________________________________________________________

　　_________________________________________________________________

　　_________________________________________________________________

　　_________________________________________________________________

第九天　点与点、点到直线的距离

　　教材例题回顾练

1. AM＝2 　x＋y－4＝0　2. (1) 　(2) 8或－8　3. (1) 2 　(2)