[tex]\displaystyle{ n = 25^{11} + 3 \cdot 5^{21} }[/tex]
[tex]\displaystyle{ n = (5^{2})^{11} + 3 \cdot 5^{21} }[/tex]
[tex]\displaystyle{ n = 5^{22} + 3 \cdot 5^{21} }[/tex]
[tex]\displaystyle{ n = 5^{21} \cdot 5^{1} + 3 \cdot 5^{21} }[/tex]
[tex]\displaystyle{ n = 5^{21} \cdot (5 + 3) }[/tex]
[tex]\displaystyle{ n = 5^{21} \cdot 8 }[/tex]
[tex]\displaystyle{ n= (5^{7})^{3} \cdot 2^{3} }[/tex]
Intrucat se poate scrie ca un nr la puterea a treia, n este cub perfect.
