a)
67 | (8^n+2 + 3×8)
8^n+2 + 3 ×8 =
= 8^n(8^2 + 3 × 8^0) =
= 8^n(64 + 3 × 1) =
= 8^n(64 + 3) =
= 8^n × 67 divizibil cu 67
b)
7 | (2^n+2 + 2^n+1 + 2^n)
2^n+2 + 2^n+1 + 2^n =
= 2^n(2^2 + 2^1 + 1) =
= 2^n(4 + 2 + 1) =
= 2^n × 7 divizibil cu 7
2)
364 = 2^2 × 7 × 13
256 = 2^4 × 2^4 = 2^8
645 = 3 × 5 × 43
5 834 = 2 × 2917