证明5^60-1是56的倍数

问题描述:

证明5^60-1是56的倍数

5^60-1 =(5^30+1)(5^30-1) =(5^30+1)(5^15+1)(5^15-1) =(5^30+1)(5^15+1)(25^3-1) =(5^30+1)(5^15+1)[(25-1)(25^2+25*1+1)] =(5^30+1)(5^15+1)[24*651] =(5^30+1)(5^15+1)[(3*8)(7*93)] =...