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

an=13.5+2.5n

an=13+2.5n

an=13.5-2.5n

an=13-1.5n

an=13.5-2.5n

Step-by-step 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

an = 13.5 - 2.5n

Answer:13-1.5n