Model the data using an exponential function f(x) = abx. hint [see example 1.] x 0 1 2 f(x) 5 4 3.2

We take the function as a sequence

Term 1 ⇒ 5 
Term 2 ⇒ 4
Term 3 ⇒ 3.2

Between terms, there is a common ratio of ⁴/₅
We get it from here:
Term 2 / Term 1 = 
Term 3 / Term 2 =  = 

When a sequence has a common ratio between term, the sequence is a Geometric Sequence


Where  is the first term, is the common ratio, and  is the term number

We have:  and 
The formula for the function is

You have to multiply n by 7 and then add that to 12. In this case, n is 6, so you do 7(6)+12.