题目

先化简，再求值：（﹣）÷，其中x=2．                        答案：【分析】先化简括号内的式子，然后根据分式的除法即可化简原式，然后将x=2代入化简后的式子即可解答本题．                                                                              【解答】解：（﹣）÷                                             =                                                                         =                                                                         =，                                                                                            当x=2时，原式==．                                                                    【点评】本题考查分式的化简求值，解题的关键是明确分式化简求值的方法．             

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