The first five terms of the sequence are: 5, 15, 45, 135, 405
The nth term of the sequence is given by:
[tex]\text{ T}_n=ar^{n-1}[/tex]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,
[tex]\text{ T}_n=5(3)^{n-1}[/tex]The function which models the n-th term of the sequence is
[tex]f(x)=5(3)^{x-1}[/tex]Option A is the right one
