This is precal I really need the help ASAP I include the pic of the question

Which one ? is the answer and how to find this answer

If a is a nonzero real number then the reciprocal of a is

Ineed big ! the cost of a school banquet is $25 plus $15 for each person attending. create a table, sketch the graph, and write an equation in slope-intercept and point-slope form that gives total cost as a function of the number of people attending. what is the cost for 77 people?