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
