Question

Find an equation for the nth term of the arithmetic sequence.
-3, -5, -7, -9, ...

Answer 1

a(n) = -3 - 2(n-1)

Explanation:

The most general formula for the nth term of an arithmetic sequence (such as this sequence is) is

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

Here a(1) = -3 and c = -2.

Thus,

a(n) = -3 - 2(n-1).