Question

The formula for any arithmetic sequence is a n = a 1 + d(n - 1), where a n represents the value of the nth term, a 1 represents the value of the first term, d represents the common difference, and n represents the term number. What is the formula for the arithmetic sequence -7, -3, 1, 5, ...? an = 5 + 4(n - 1) an = 4 + (-7)(n - 1) an = -7 + 4(n - 1) an = -7 + 5(n - 1)

Answer 1

a1 = - 7

d = 4

an = - 7 + 4(n - 1)

Try a4

a4 = - 7 + 4(4 - 1)

a4 = -7 + 4*3

a4 = -7 + 12

a4 = 5 which it does.