In , approximately cars and trucks were classified as flex fuel,

which means they could run on gasoline or ethanol.

In , that number increased to about .

Find how many more cars and trucks were flex-fuel in .

Let represent the additional number of cars and trucks (in millions) from to .

                (Original equation)

    (Subtract  from each side)

         (Apply additive inverse property : )

In , more cars and trucks were classified as flex fuel than in .

In , more cars and trucks were classified as flex fuel than in .