Will give brainliest if right, please help me with this math question

Arestaurant charges $100 to rent its banquet room for an event. it also charges $15 to serve dinner to each guest. write an equation for the total cost of the banquet room in terms of the number of guests. deine your variables. what is the total cost of the banquet room for 20 guests?

Math it's appreciated. (picture provided)

Ade and abc are similar. which best explains why the slope of the line between points a and d is the same as the slope between points a and b?