# Thread: Deriving a functions model

1. ## Deriving a functions model

For his services a private investigator requires a $700 retention fee plus$60 per hour.

Let x represent the number of hours the investigator spends working on a case.

a) find a function f that models the investigator's fee as a function of x.

b)f^-1 and f^-1(1000).What does the answer represent?

2. ## Re: Deriving a functions model

What have you tried?

Where are you stuck?

We help you solve problems. We're not here to solve them for you.

3. ## Re: Deriving a functions model

List the quantities that will vary with time and the ones that will remain fixed. It helps with sorting things out.