确定不等式组中字母系数的取值范围,关键是要弄清不等式组解集的意义.一般来说,不等式组的解集可用下面的口诀来确定:我们把上面4个不等式组称为不等式组的最简形式.一般地,我们把所给不等式组化成最简形式之后,可根据所给解集逆向确定字母系数的取值范围,下面举例说明. The key to determining the range of letter coefficients in an inequality group is to understand the meaning of the set of inequality sets. In general, the solution set for an inequality set can be determined by the following formula: We call the above four inequality groups inequality sets In general, after we group the inequality into the simplest form, we can inversely determine the value range of the letter coefficients according to the given solution set as follows.