Answer:
an = - 7n+35
Explanation:
In an arithmetic sequence, the difference between consecutive terms is constant. To find this difference, we can subtract the first term from the second term and the second term from the third term, etc.
a2 - a1 = 21 - 28 = -7
a3 - a2 = 14 - 21 = -7
Since the difference between consecutive terms is the same, we can conclude that the difference is -7.
The nth term in an arithmetic sequence can be found using the formula: an = a1 + (n-1)d, where d is the common difference.
For this sequence, the nth term can be found as: an = 28 + (n-1)(-7) = 28 - 7(n-1) = 28 - 7n + 7 = 35 - 7n.
So, the formula for the nth term in this arithmetic sequence is an = - 7n+35