A.4.16.1 Shopping for Cookbooks

Lin is comparing the cost of buying cookbooks at different online stores. Store A sells them at $9 each and offers free shipping. Store B sells them at $9 each and charges $5 for shipping. Store C sells them at dollars and charges $5 for shipping. Store D sells them at dollars and charges f dollars for shipping. 1. Write an equation to represent the total cost, T, in dollars as a function of n cookbooks bought at each store.

2. Write an equation to find the number of books, n, that Lin could buy if she spent T dollars at each store.

What happened with the output and inputs from question 1 and 2?