Respuesta :

Panoyin
19, 13,  7,  1,…
  - 6  - 6  - 6

Something that is explicit to the problem is tat it has a common difference of -6.

a(n) = a₁ + d(n - 1)
a(n) = 19 - 6(n - 1)
a(n) = 19 - 6(n) + 6(1)
a(n) = -6n + 19 + 6
a(n) = -6n + 25