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
