At Billy's Burgers, two bacon cheeseburgers and three orders or curly fries would cost $ 16.45. One order of curly fries and three bacon cheeseburgers would cost $ 16.66. What is the cost of one bacon cheeseburger?
I think I leaned how to do this before but I just can not remember how to do this. Please show me how to do this in steps.

Mrs. julien’s and mrs. castillejo’s classes are selling cookie dough for a school fundraiser. customers can buy packages of macadamia nut chip cookie dough and packages of triple chocolate cookie dough. mrs. julien’s class sold 25 packages of macadamia nut chip cookie dough and 30 packages of triple chocolate cookie dough for a total of $221.25. mrs. castillejo’s class sold 5 packages of macadamia nut chip cookie dough and 45 packages of triple chocolate cookie dough for a total of $191.25. (a) write the system of equations that model the problem. be sure to explain which equation represents which situation. (b) find the cost of each type of cookie. show your work. (c) explain which method you used to solve the system and why you chose that method.