Give an example of an open equation

In the coordinate plan (-6,9) b (3,9) c (3,3) def is shown in the coordinate plan below

What are “like terms”? why can we only add like terms?

Need ! the total ticket sales for a high school basketball game were $2,260. the ticket price for students were $2.25 less than the adult ticket price. the number of adult tickets sold was 230, and the number of student tickets sold was 180. what was the price of an adult ticket?