Do i have 4 right? ? and how would i do 5 just take 20 and = it to 4x and then divide? ? so it would look like 20=4x den 5=x is this right or am i wrong tell me i need to asap plzz (so don't mind the hand writing)

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?