Could someone explain how to do this? i did it wrong the first time.

Arestaurant offers a $12 dinner special that has 5 choices for an appetizer, 12 choices for an entrée, and 4 choices for a dessert. how many different meals are available when you select an appetizer, an entrée, and a dessert? a meal can be chosen in nothing ways. (type a whole number.)

Which system of linear inequalities is represented by the graph? + l tv x-3y > 6 and y > 2x o x + 3y > 6 and y o x-3y > 6 and y> 2x o x + 3y > 6 and y > 2x + 4 la +

What is the missing step in this proof ?