We are told that the first term is 2. The next term is 7(2) = 14; the third term is 7(14) = 98. And so on. So, the first term and the common ratio (7) are known.
The nth term of this geometric series is a_n = 2(7)^(n-1).
Check: What is the first term? We expect it is 2. 2(7)^(1-1) = 2(1) = 2. Correct.
What is the third term? We expect it is 98. 2(7)^(3-1) = 2(7)^2 = 98. Right.
