一次函数是反映现实世界的数量关系和变化规律的数学模型;它是初中学习中最基本的一种函数,课本是按照概念(一次函数表达式)→图象→性质→应用来展开的,学习本章要学会运用待定系数法、数形结合的思想研究问题.(由数到形,将条件直观化;由形到数,寻求等量关系;数形结合最终获得问题的解决方法),另一方面,应初步体会数学学习中的“问题情景——建立模型——解释应用 The primary function is a mathematical model that reflects the quantitative relationship and the law of change in the real world; it is the most basic function in the junior high school study. The textbook is developed according to the concept (primary function expression) → image → property → application. This chapter should learn to use the undetermined coefficient method and the idea of ​​combining number and shape to study problems. (from number to shape, visualize conditions; from shape to number, seek equal number of relations; number and shape combine to finally obtain solution to the problem), another On the other hand, we should initially understand the "situation of problems in mathematics learning - establishing models - explaining applications