Question

Write the explicit formula for the arithmetic sequence.

Answer 1

Answer:

an = 9n -16

Step-by-step explanation:

First find the common difference, d

Take the second term and subtract the first

2 - (-7) = 2+7 = 9

We are adding 9 each time

Check 2+9 =11, check  11+9 = 20  check

The first term in the sequence is a1  so a1 =-7

an = a1 + d(n-1)

an = -7 + 9(n-1)

Distribute

an = -7 +9n-9

Combine like terms

an = 9n -16