Can someone me figure out the answer?

You will break even on the car wash when you buy 13.5 gallons. As long as you buy that or more, it is cheaper to get the car wash.

Step-by-step explanation:

In order to find this, we need to create equations for both situations. If we let x equal the amount of gallons purchased, we can model the first equation as:

f(x) = 3.35x

And the second equation as:

f(x) = 3.05x + 4.05

Then to find when they equal each other, we can set the two equations equal to each other and solve for x.

3.35x = 3.05x + 4.05

0.30x = 4.05

x = 13.5

This means once you buy 13.5 gallons, the prices will be the same. Any amount over that and the car wash will be cheaper