What is the general equation of a cosine function with an amplitude of 3, a period of 4 pi, and a horizontal shift of Negative pi?

How do you do this geometry problem

Christine went shopping and bought each of her six six nephews a? gift, either a video costing? $14.95 or a cd costing? $16.88. she spent ? $ 97.42 97.42 on the gifts. how many videos and how many cds did she? buy?

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