Answer: 4n - 12
Explanation:
We can see that with each step, we are increasing our value by 4.
This is represented in "4n"
Our term "a1" is -8, which means to find "a0" we need to simply subtract 4 "a1" (-8), effectively working in reverse.
This should give us 4n (increasing by 4 each step) minus 12 (our starting value)