近年来,在中考中出现了已知不等式组的解集,求不等式组中字母系数取值范围的题目.在教学时,我借用数轴,利用数形结合分类讨论的数学思想解决这类题目,收到了良好的教学效果.下面举例介绍这种方法的应用. In recent years, in the senior high school entrance examinations, we have solved the set of known inequality groups and solved the problem of the range of the letter coefficients in the inequality group.In the teaching, I borrowed several axes, Received a good teaching results. The following examples illustrate the application of this method.