Question

For the sequence -27, -12, 3, 18, ..., the expression that defines the nth term where a1 = -27 is
A. 15 --27n
B. 15-27 (n-1)
C. -27 + 15n
D. -27+15 (N-1)

Answer 1

Answer:

D. -27+15 (N-1)

Step-by-step explanation:

-27, -12, 3, 18

Take the second term and subtract the first term to find the common difference

-12 - (-27)

-12+27 = 15

The common difference is +15

We are adding 15 each time

The formula for an arithmetic sequence is

an = a1+d(n-1)

an = -27 +15(n-1)