Question

Find the thirteenth term of an arithmetic sequence if the first term is 3 and the common difference is 3

Answer 1

39

Explanation:

Answer 2

39

Explanation:

The most general form of the equation predicting the nth term of an arithmetic sequence when the first term and the common difference are known is

a(n) = a(1) + (n-1)d, where d is the common difference.

Here we have a(n) = 3 + 3(n-1).

Thus, the 13th term is a(13) = 3 + 3(13-1), or a(13) = 3 + 3(12) = 39.

The 13th term is 39.