Answer:
I have solve it in above picture
x = -1
y = -5
Step-by-step explanation:
9(2y+9) - 8y = 31
18y + 81 - 8y = 31
10y + 81 = 31
10y = -50
2(-5) + 9 = x
-10 + 9 = x
-1 = x
cost of 1 gallon gas = $2.09
cost of 3.785 litres gas = $2.09 ( 1 gallon = 3.785 litres)
cost of 1 litre gas = 2.09/3.785
cost of 18 litres gas = 2.09/3.785 * 18 = $20.982
first one: 1 1/2 pints
second: 44 months
40 %
