Answer:
C
Step-by-step explanation:
to have a common difference of -8.5, the sequence has to consistently go down by 8.5.
in the first one, y would go up by 2 every time x goes up by 1, so its not that one.
in the second one, it does go down by 8.5 the first time but the next time it goes down by 4.25, so it's not consistent.
in the third one, each time it goes down by 8.5 so this is the answer.
the fourth one also isn't correct because the graph shows that it is going up, so you know for sure it's not that one.
