Which answer is the explicit rule for the sequence 11,8.5,6,3.5,1

Answer: 3.5-2.5n

Explanation:

To find the common difference take the end term and subtract the first term:

8.5 - 11 = - 2.5

Take the third term and subtract the 3rd term to verify:

6-8.5 = - 2.5 check

The formula for an arithmetic sequence is:

an = a1+d (n-1)

an = 11 - 2.5 (n-1)

Distribute:

an = 11 - 2.5n+2.5

Combine terms:

answer = 13.5 - 2.5n