第一章《因式分解》测试题

一、填空题. 把下列各式因式分解（30分）                                    

1.           a — 9 =                                  

2.       a+ a =                                                        

3.       —5 a+ 25a =                                                   

4.       3 ab — 6a bc =                                              

5.       a（a —3）— 5（a—3）=                                         

6.       — 6a b（x+y）+12 ab（x+y）=                                                                

7．（a+b）（a—c）—（a—b）（c—a） =                                                                 

8．y（y—5）—7（5—y）=                                                          

9．４a—b=                      

10．16x— y=                                                    

二．把下列各式因式分解（要求写出解题过程）（30分）                                                 

11．mn— m                                                                   

  解：                                                

12． x— 7                                                                      

解：                                                 

． a—5a +