Exercise 72 Page 577

We are given two terms of an arithmetic sequence.

a_{4} = - 2.4 and a_{6} = 2

With the information provided, we want to find the common difference

d

and the first term

a_{1} .

Recall that the common difference is the difference between any two consecutive terms. Since the terms we are given are not consecutive, we will divide their difference by the difference of their positions.