How do you know whether to add or subtract when using the distributive property to multiply?

Distributive property is characterized by the use of parenthesis, wherein you distribute the outside number to each term inside the parenthesis by multiplication. You'll just have to copy the operation inside the parenthesis as it is, whether addition or subtraction. For example,

3(10+4-3) = 3(10) + 3(4) - 3(3) = 33

38 dollars is your answer.