Question

Matthew is making a sequence in which -3 is added to each successive term. The 6th term in his sequence is -1. What is the 1st term in his sequence?

Answer 1

The first term is 14.

Explanation:

The general formula for this kind of sequence (arithmetic) is a(n) = a(1) + (n-1)c, where c is the common difference. Here, we have a(6) = -1 = a(1) + (6-1)(-3), or -1 +15 = a(1). The first term is 14.