函数问题是初中阶段重要的知识点之一,函数中的许多概念与其图象有着密不可分的关系,因此,充分运用数形结合思想解决函数问题十分重要.一、求函数的解析式例1已知一次函数的图象经过一、二、三象限,请写出一个符合题意的解析式.分析首先根据题意画出草图(如图1).由此,可任意写? The function problem is one of the important knowledge points in the junior high school. Many concepts in the function are inextricably linked with the image. Therefore, it is very important to fully use the idea of ​​combination of number and shape to solve the function problem. First, the analytical formula of the function is given in Example 1. Know that the image of the primary function passes through one, two, or three quadrants. Please write an analytical expression that matches the meaning of the question. The analysis first draws a sketch based on the question (as shown in Figure 1). Thus, it can be written arbitrarily?