Sally wants to purchase some school supplies. Notebooks cost $3 each and pens cost $2 each. Sally is not allowed to purchase more than 12 items. Sally knows that she will need at least 4 notebooks and at least 5 pens to be prepared for school. Write an equation that represents the constraints of Sally's purchasing.
You have to do 3x4 because each notebook is 3 dollars and she needs at least 4 of them for school and then do 2x5 because each pen cost at least 2 dollars and she needs at least 5 pens for school. So the equation would be (3x4)+(2x5)