Respuesta :

this sequence is decreased by 3 for every digit

so

-3n+18

-3n+18

1) Find the difference (Decreasing by -3)
2) N is -3
3) Find the number before the first digit (15+3 = 18) as if we follow the difference of -3: 18-3 gives us 15.

Therefore, the nth term is -3n+18