Answer:
= 3n - 87
Step-by-step explanation:
There is a common difference between consecutive terms , that is
- 81 - (- 84) = - 78 - (- 81) = - 75 - (- 78) = - 72 - (- 75) = 3
This indicates the sequence is arithmetic with nth term
= a₁ + (n - 1)d
where a₁ is the first term and d the common difference
Here a₁ = - 84 and d = 3 , then
= - 84 + 3(n - 1) = - 84 + 3n - 3 = 3n - 87