Answer:
It's the second choice
Step-by-step explanation:
Note that the numbers values increase by 5 .
When n = 0 , we have -9 + 5(0) = -9
when n = 1 it is -9 + 5(1) = -4
when n = 2 it is -9 + 5(2) = 1 and so on.
when n = 15 (the last term) 66 = -9 + 5(15).
We can write the summation as:
n=15
∑ (-9 + 5n)
n=0.