Question

The number of members f(x) in Joe's health club increased by 25% every year over a period of x years. The function below shows the relationship between f(x) and x: f(x) = 15(1.25)x Which of the following graphs best represents the function?

Answer 1

The answer is C

Explanation:

Because!

Answer 2

It is given that , number of members f(x) in Joe's health club increased by 25% every year over a period of x years.

The relationship between f(x) and x is given as:

`f(x) = 15(1.25)^x`

Replacing f(x) by y, in the above equation

y=
`15(1.25)^x`

To draw the graph without the help of Desmos, find diifferent value of y, for different values of x, For example , for x=1

We get , y=
`15(1.25)^1`= 18.75

For, x=2

y=
`15(1.25)^2`=15 × 1.5625=23.4375

For, x=3

y=
`15(1.25)^3`= 29.296875

So, for different values of x, we get different values of y. Mark these points in the coordinate plane, and join them . You will get the graph of the above function :⇒ f(x)=
`15(1.25)^x`

Graph is depicted below.