Answer:
a(87) = -590
Step-by-step explanation:
Notice how each term of this arithmetic sequence is equal to the sum of the previous term and the common difference, -12.
The general formula a(n) = a(1) + (n - 1)d becomes:
a(n) = 12 - 7(n - 1)
and the 87th term a(87) = 12 - 7(87 - 1), or
a(87) = 12 - 7(86)
a(87) = -590
