Erica works at a movie theater for x hours a week after school, which pays $4 an hour. She has accepted a job that pays $8 an hour at a bakery working y hours a week. She will work both jobs. She is able to work no more than 15 hours a week, due to school commitments. Erica wants to earn at least $80 a week, working a combination of both jobs. a. Write a system of inequalities that can be used to represent the situation. b. Graph these inequalities on the set of axes.