Define your variables:
At Manny's taco shop, you can get an order of chips and two tacos for $9.25. The cost for two orders of chips and five tacos is $21.75.
x = Chips
y = Tacos
Write your system of Equations:
You can get an order of chips and two tacos for $9.25.
1 Chips + 2 Tacos = 9.25
x + 2y = 9.25
The cost for two orders of chips and five tacos is $21.75.
2 Chips + 5 Tacos = 21.75
2x + 5y = 21.75
Solve The System:
First equate the coefficient - in this case x:
(x + 2y = 9.25) * 2 = 2x + 4y = 18.50
2x + 4y = 18.50
2x + 5y = 21.75
Minus the equations from each other to remove the coefficient you equated:
(2x + 5y) - (2x + 4y) = 21.75 - 18.50
(2x - 2x) + (5y - 4y) = 21.75 - 18.50
y = 3.25
Answer The Question Being Asked:
What is the cost of an order of chips?
1 Taco = $3.25
y = 3.25
Substitute this into the equation.
x + 2y = 9.25
x + (2 * 3.25) = 9.25
x + 6.50 = 9.25
Rearrange to find x:
x = 9.25 - 6.50
x = 2.75
Chips = $2.75
$2.75
