Final answer:
The given sequence is not arithmetic as it does not have a consistent pattern.
Step-by-step explanation:
The given sequence is 9, 75, 3, 1... To determine if the sequence is arithmetic and find the common difference, we need to check if the sequence has a consistent pattern. If the difference between consecutive terms is the same, then the sequence is arithmetic.
9 - 75 = -66
75 - 3 = 72
3 - 1 = 2
As we can see, the differences between the consecutive terms are not the same. Hence, the given sequence is not arithmetic.