What is a 15 of the sequence - 7, 2, 11, ... ?

A. 128

B. 110

C. 136

D. 119

D. 119

Step-by-step explanation:

To find the common difference, we take the second term and subtract the first term

2 - (-7) = 9

We check by taking the third term and subtracting the second

11-2 = 9

The common difference is 9

The formula for an arithmetic sequence is

an = a1 + d (n-1)

where a1 is the first term, d is the common difference and n is the number of the term in the sequence

a1=-7, d=9 and we are looking for the 15th term so n=15

a15 = - 7 + 9 (15-1)

a15 = - 7+9 (14)

=-7 + 126

= 119