Answer:
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
