Question

For the sequence -27,-12, 3, 18,..., the expression that defines the nth term where a, = -27 is

Answer 1

-27+15 (N-1)

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)