Shelly has a gift card for her favorite restaurant for $15. She wants to treat a group of her friends sandwiches at the restaurant. Sandwiches cost $4.50 each. Write an equation that model the total money Shelly owes if she buys x sandwiches after using the gift card.

Answer: the equation is y = 4.5x - 15

Step-by-step explanation:

Let x represent the total number of sandwiches that shelly bought at her favorite restaurant.

Shelly has a gift card for her favorite restaurant for $15. Sandwiches cost $4.50 each. If she buys a total number of x sandwiches, it means that that the total cost will be 4.5*x = $4.5x

Let y represent the amount of money that she owes after buying x sandwiches. Therefore

y = 4.5x - 15