Question

Write an equation for the nth term of the arithmetic sequence
18, 30, 42, 54, 66,
A. an = 30n + 6
B. an = n + 18
C. an = 12n + 6
D. an = 18n + 12

Answer 1

The arithmetic sequence is increasing in 12 each time

18, 30, 42, 54, 66
12n 12, 24, 36, 48, 60

To get from 12n to the arithmetic sequence, you add 6 each time

Therefore the answer is C - an = 12n + 6