Hello!
To solve for this word problem, note that the variable n represents the amount of people going to the school banquet. With this in mind, since you know the number of people who attended is 80, plug this value in place of n into the given expression, 73+11n. When you plug this in, you should get 73+11(80). Then, simplify as according to your order of operations (multiply 11 and 80 and then add 11 to it) and you should get $953 as your answer. :)