一次函数是三种常见函数(一次函数、二次函数和反比例函数)中最为简单的函数,因此颇受中考命题者的青睐.下面就有关一次函数的常见题型分类介绍如下.一、考查函数关系式的建立例1已知y-1与(x-1)2成正比例,且当x=-1时,y=3.求当x=3时,y+____.解:把y-1和(x-1)2分别视为一个整体,由正比例函数定义,可设y-1=k(x-1)2(k≠0),即y=k(x-1)2+1. The first function is the simplest function of the three common functions (primary, quadratic, and inverse) and is therefore favored by the proctors. Here’s a breakdown of common questions about a function: Relational establishment example 1 It is known that y-1 is proportional to (x-1)2, and when x=-1, y=3. When x=3, y+____. Solution: put y-1 The sum (x-1)2 is considered as a whole, defined by a positive-sizing function, and can be set as y-1=k(x-1)2(k≠0), that is, y=k(x-1)2+1.