Total cost of repairing a car is the sum of the amount paid for parts and the amount paid for labor.

Let h represent the number of hours spent on labor.

Equation based on the verbal model is

  (Subtract 78 from each side) \ \

                         (Subtract: ) \ \

                               (Apply additive identity property: ) \ \

                          (Divide each side by 45) \ \

                                 (Cancel common terms) \ \

                                      (Divide: ) \ \ To repair the car it takes two hours.