Question

10 Points!

Find an equation for the nth term of the arithmetic sequence.
-1, 2, 5, 8, ...

an = -1 + 3(n)
an = -1 + 3(n - 1)
an = -1 + 3
an = -1 + 3(n + 1)

Answer 1

In this sequence, a₁ equals -1. 

The difference between each term is +3, so the coefficient for n will be 3.

In the sequence, a₂ equals 2. The following equation will fit this sequence, and will be your answer:

$a_n = -1 + 3(n - 1)$

Proof:
$a_1 = -1 + 3(1 - 1) = -1 + 3(0) = -1$

$a_2 = -1 + 3(2 - 1) = -1 + 3(1) = -1 + 3 = 2$