Let x = calories in a cheeseburger
Let y = calories in an order of small fries
Four cheeseburgers and five small fries have 2,310 calories. Therefore
4x + 5y = 2310 (1)
Three cheeseburgers and two small fries have 1,330 calories. Therefore
3x + 2y = 1330 (2)
Equations (1) and (2) model the given situation.
To solve, multiply (1) by 2, and multiply (2) by 5 to obtain
8x + 10y = 4620 (3)
15x + 10y = 6650 (4)
Subtract (3) from (4).
7x = 2030
x = 290
From (1), obtain
5y = 2310 - 4*290 = 1150
y = 230
Answer:
The two equations are
4x + 5y = 2310
3x + 2y = 1330
The solutions are x = 290, y = 230.