Olivia is making model cars to go on shelves in her room. The number of wheels she uses is a function of how many cars she makes: if she makes 1 car, she uses 4 wheels; if she makes 2 cars, she uses 8 wheels; if she makes 3 cars, she uses 12 wheels; and so on. She has exactly 28 wheels she can use to make cars. What is the domain and range for the function?