Explain why the greatest common factor of two numbers is sometimes 1

Answer these questions showing your work plz

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.)

The distributive property allows you to say that 3(x − 1) = 3x −