[tex]\it N=5(\underbrace{\it1+5+5^2}_{=31})+5^4(1+5+5^2)+\ ...\ +5^{88}(1+5+5^2)=\\ \\ \\=31\cdot(5+5^4+\ ...\ +5^{88})\in M_{31} \Rightarrow N\ \vdots\ 31[/tex]
Răspuns:
Explicație pas cu pas:
