Answer:
39
Step-by-step 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.
