Just substitute in values into the equation corresponding to the x,y:
To solve for a missing y value, substitute the corresponding x value, so 0, 2.33, and 6.25.
To solve for x, set the equation equal to the x and solve.
x's: 0 .25 2.33 4.5 6.25
y's: 5 5.75 14.99 18.5 23.75
--------------------- By scenario, you could make that equation 3x + 5 the rental time of a very cheap carper cleaner service. They charge 5 dollars as the static fee, and 3 dollars per hour