An electrician earns 100 dollars for a project installing light fixtures. She must pay for the light fixtures herself and they cost 2 dollars and 50 cents each at the hardware store. Create an equation to represent her profit from the project. Let x represent the number of light fixtures and y represent her total profit (the amount of money she has left over after paying for the light fixtures).
If she wants to earn a profit of 75 dollars from this project, how many fixtures should she plan to install? Show your work.