二次函数、二次不等式、二次方程是高中数学的重要内容,它把中学数学各个分支紧紧地联系在一起.以“三个二次”为载体,综合二次函数、二次不等式、二次方程交叉汇合处为主干,构筑成知识网络型代数推理题,在高考试题出现的频率相当高, Quadratic functions, quadratic inequalities, and quadratic equations are important aspects of high school mathematics. They link the various branches of middle school mathematics tightly. They use the “three quadratic” vectors as carriers, integrated quadratic functions, and quadratic inequalities. The intersection of quadratic equations is the backbone, and it is constructed as a knowledge network-type algebraic reasoning problem. The frequency of occurrence of high-test questions is quite high.