The first five terms of the sequence are: 5, 15, 45, 135, 405
The nth term of the sequence is given by:
a = first term of the sequence =5
r = common ration = 3
Note that the common ratio is calculated by diving each term by its previous term. For instance, 15 divided by 5 is 3.
Therefore,
The function which models the n-th term of the sequence is
Option A is the right one