Explicație pas cu pas:
[tex](9 {}^{n} \times 2 {}^{n + 1} + 6 {}^{n + 2} \times 3 {}^{n} - 18 {}^{n} ) = \\ (3 {}^{n} \times 3 {}^{n} \times 2 {}^{n} \times 2 + 3 {}^{n} \times 2 {}^{n} \times 6 {}^{2} \times 3 {}^{n} - 3 {}^{n} \times 3 {}^{n} \times 2 {}^{n} ) = \\ (3 {}^{n} \times 3 {}^{n} \times 2 {}^{n} )(2 + 36 - 1) = \\ (3 {}^{n} \times 3 {}^{n} \times 2 {}^{n} ) \times 37[/tex]
De aici rezulta ca nr se împarte la 37
