What is he price of a hamburger and cheeseburger at this restaurant

h+3c=$9.00
2h+c=$5.50

h+3c=$9.00

2h+c=$5.50

h = 9 - 3c

2(9 - 3c) + c = 5.5

18 - 6c + c = 5.5

12.5 = 5c

2.5 = c