二次根式的化简与运算通常是应用根式的基本性质和运算性质、根式的运算法则及分母有理化来进行的．初学时由于概念不清、判断问题不明确和运算上的不合理而容易产生种种错误，以下就一些例子作简单的分析．例1化简错误解答正确解答原式分析因为有意义，所以－x3≥0，即x≤0， The simplification and operation of quadratic roots is usually performed by applying the basic nature and operation properties of the root, the root algorithm, and the rationalization of the denominator. At the time of beginners, due to unclear concepts, unclear judgment questions, and unreasonable calculations, it is easy to produce various errors. Here are some examples for simple analysis. Example 1 Simplification Errors Correctly Answered The original analysis is meaningful, so -x3 ≥ 0, ie x ≤ 0,