Question

若3×9^m×27^m=3²¹，則m=　　　　　　．                                                 

Answer 1

　4　．                                                                                             

【考點】冪的乘方與積的乘方；同底數冪的乘法．                                         

【分析】根據冪的乘方和積的乘方的運算法則求解．                                      

【解答】解：3×9^m×27^m=3×3^2m×3^3m=3^5m+1，                                            

故5m+1=21，                                                                                    

解得：m=4．                                                                                     

故答案為：4．                                                                                   

【點評】本題考查了冪的乘方和積的乘方，解答本題的關鍵是掌握冪的乘方和積的乘方的運算法則．