The tank holds 18 gallons of gasoline.
Let x represent the number number of gallons of gasoline that the tank of Lydia's car hold.
Lydia gas tank was 3/4 full when she left on a trip. It means that the amount of gasoline in the tank was 3x/4 gallons.
She used 8 gallons of gasoline during her trip. The amount that would be left is
3x/4 - 8
Now, 5.5 gallons of gasoline remain in the gas tank. It means that
3x/4 - 8 = 5.5
Multiplying both sides of the equation by 4, it becomes
3x - 32 = 22
3x = 22 + 32
3x = 54
x = 54/3
x = 18
lol we need to see what the question is asking about