题目

为了发展旅游经济，我市某景区采用灵活的售票方法吸引游客．门票定价为50元/人，非节假日打a折售票，节假日按团队人数分段定价售票，即m人以下（含m人）的团队按原价售票；超过m人的团队，其中m人仍按原价售票，超过m人部分的游客打b折售票．设某旅游团人数为x人，非节假日购票金额为y1（元），节假日购票金额为y2（元）．y1、y2与x之间的函数关系如图所示．   (1)观察图象可知：a＝_______；b＝_______；m＝_______．   (2)直接写出y1、y2与x之间的根据史密斯的家庭树填空 　　Nora is an old woman. She has a big family. There are ___1___ people in her family. Her ___2___ is Dan. They have three___3___, two ___4___ and a ___5___. Peter's ___6___ is Alice. Mike and Amy are their ___7___. Becky is Peter's___8___. Rose and Becky are ___9___. Alice is Peter's ___10___, and she is Mike and Amy's ___11___. John and Rose are ___12___ and ___13___. Their ___14___ is Linda. Rose is Mike's___15___. Becky is Amy's___16___. Dan is the children's___17___. Nora is their ___18___.