Question

Sue buys 5 notebooks and 3 binders for 21.56. Tim buys 4 notebooks and 2 binders for 15.80. how much is each item?

Answer 1

There are two values we do not know - the cost of a notebook and the cost of a binder
Let x be the cost of a notebook.
Let y be the cost of a binder.
5*(cost of notebook) + 3*(cost of binder) = 21.56
4*(cost of notebook) + 2 * (cost of binder) = 15.80
Replacing with x and y
5x + 3y = 21.56
4x + 2y = 15.80
Ok so far?

Answer 2

Yes