A squared plus b squared

How to do this , and can some one explain

Aclothing store has the sign shown in the shop window. pani sees the sign and wants to buy 3 shirts and 2 pairs of jeans. the cost of each shirt before the discount is $12, and the cost of each pair of jeans is $19 before the discount. write and simplify an expression to find the amount pani pays if a $3 discount is applied to her total

Acd that is originally priced at $15.85 red-tagged for the sale. what is the sale price of the cd