【摘 要】
：
字母取值范围问题是初中数学学习中的常见问题,在中考中屡见不鲜.解答它们,要注意从构造不等式(组)入手.现以中考题为例介绍如下:一、与代数式有关的字母取值范围例1(2016年
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字母取值范围问题是初中数学学习中的常见问题,在中考中屡见不鲜.解答它们,要注意从构造不等式(组)入手.现以中考题为例介绍如下:一、与代数式有关的字母取值范围例1(2016年广州市中考题)代数式(9-x)~(1/2)有意义时,实数x的取值范围是______.分析:若代数式(9-x)~(1/2)有意义,则它表示非负数9-x的算术平方根.为此,9-x≥0.
The problem of alphabetic value range is a common problem in junior high school mathematics learning, and it is not uncommon to find it in the middle school entrance examinations.To answer them, we should pay attention to construct the inequality (group) to start with the examination questions as an example as follows: First, the algebraic letter values The range of real number x is ______ when algebraic formula (9-x) ~ (1/2) is significant. Example: 2) is significant, then it represents the arithmetic square root of the non-negative 9-x, for which 9-x ≥ 0.
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