一、在二次根式的定义“一般地 ,式子 a (a≥ 0 )叫做二次根式”中 ,条件 a≥ 0常被命题者作为隐含条件放置在题目中 ,若不注意挖掘 ,要么对问题一筹莫展 ,要么导致错误的结论。例 1 .阅读下面一题的解题过程 ,请判断是否正确 ?若不正确 ,请写出正确的解答。已知 a为实数 ,化简 First, in the definition of the quadratic root formula “generally, the formula a (a ≥ 0) is called a quadratic radical”, the condition a ≥ 0 is often placed by the proposition as an implied condition in the subject. If one does not pay attention to digging, either Failing to do anything about the problem leads to erroneous conclusions. Example 1. Read the problem solving process of the following question. Please judge whether it is correct. If not, please write the correct answer. Know that a is a real number and simplify