Answer:
275 hamburgers.
Step-by-step explanation:
Let hamburgers = x
Let cheeseburgers = y
A combined total of 478 were sold on sunday, with 72 cheeseburgers less than hamburgers. Set the equations:
x + y = 478
y = x - 72
Plug in x - 72 for y:
x + (x - 72) = 478
Combine like terms:
2x - 72 = 478
Isolate the variable, x. Note the equal sign, what you do to one side, you do to the other. Do the opposite of PEMDAS. First, add 72 to both sides:
2x - 72 (+72) = 478 (+72)
2x = 478 + 72
2x = 550
Isolate the variable, x. Divide 2 from both sides:
(2x)/2 = (550)/2
x = 550/2
x = 275.
275 hamburgers were sold on sunday.
