Question

The first term of an arithmetic sequence is -3 and the fifteenth term is 53.
What is the common difference of the sequence?

Answer 1

this is where knowing a formula is helpful

Answer 2

an = a1 +d(n-1) is the general set up; and we can solve for d

an - a1
------ = d
n-1

Answer 3

n = 15 in this case, and an = 53, whereas a1 = -3

Answer 4

So it would look like this
53+3
--------
15-1?