一元二次方程字母系数取值范围求解是中考题中出现频率相当高的题型之一。解这类问题一般用到判别式和韦达定理的知识,这两个知识点既可各自分开使用,电可综合使用,有时还辅以其它手段。特别要注意的是使用判别式要考虑二次项系数a≠0,使用书达定理时先确保△≥O,现具体淡谈解法。 The solution of the range of values ​​of the one-dimensional quadratic equation letter coefficient is one of the questions of the type with high frequency in the examination questions. Solving such problems generally uses discriminant and Vedic theorem knowledge. These two knowledge points can be used separately, electricity can be used comprehensively, and sometimes supplemented by other means. Special attention should be paid to the use of discriminants to consider the quadratic coefficient a≠0. When using the book theorem, first ensure that △ ≥ 0, and now specifically talk about the solution.