For this case we have the following data:
A shipping fee of $ 1.99 is charged for each book sold.
There is a fixed fee of 3 dollars per order.
We must express the total cost by a function of the form
.
If x represents the number of books sold, we have an expression of the form:
![f (x) = 1.99x + 3](https://tex.z-dn.net/?f=f%20%28x%29%20%3D%201.99x%20%2B%203)
That is, according to the number of books sold, represented by x, a different value will be obtained for the total cost given by f (x). For example:
If 3 books are sold, we have:
![f (3) = 1.99 (3) +3\\f (3) = 5.97 + 3\\f (3) = 8.97](https://tex.z-dn.net/?f=f%20%283%29%20%3D%201.99%20%283%29%20%2B3%5C%5Cf%20%283%29%20%3D%205.97%20%2B%203%5C%5Cf%20%283%29%20%3D%208.97)
Thus, the total cost of 3 books is 8.97 dollars.
Answer:
![f (x) = 1.99x + 3](https://tex.z-dn.net/?f=f%20%28x%29%20%3D%201.99x%20%2B%203)