Luther and Darell, both teachers, are adding books to their class libraries. Luther's classroom started out with a collection of only 10 books, but he plans to purchase an additional 4 books per week. Darell's library started out with 30 books, and he has enough money in his budget to purchase another 2 books per week. At some point, the two teachers' libraries will contain the same number of books. How many books will each class have? Write a system of equations, graph them, and type the solution.