Answer:
Here we have two inequalities.
P is price of the gallon,we have that:
$2.40 ≤ P ≤ $2.65
C is the amount of gallons that Ricardo buys each week.
8,5 ≤ C ≤ 11
Now, with this you can find the maximum and minimum amount that he can spend on a week.
The minimum is when he buys only 8.5 gallons and the price per gallon is $2.40
Cost = 8.5*$2.40 = $20.4
The maximum cost is when he buys 11 gallons, and the price of the gallon is $2.65
Cost = 11*$2.65 = $29.15
So the amount that he spends per week in gas, S, is:
$20.4 ≤ S ≤ $29.15
The answer is a parallelogram
Linear combination method just means to add the equations so that one variable with cancel. In this case the a values are already set up so that they will cancel.
2a + 3b = 1
-2a + b = 11
4b = 12
b = 3
now put 3 back into either of the original equations and solve for a.
2a + 3(3) = 1
2a + 9 = 1
2a = -8
a = -4
(-4,3)
