Final answer:
The total expenses for the delivery truck after adding the cost of the oil change ($55) and the installation of special shelving units ($537) is $592.
Step-by-step explanation:
To calculate the total expenses for the delivery truck, we simply need to add the two transactions related to its maintenance and upgrade. The oil change cost $55, which is a regular maintenance expense. The installation of special shelving units was $537, which improved the operating efficiency and can be considered a capital improvement rather than an expense for accounting purposes. However, assuming both costs are treated as expenses for this exercise, the total expenses would be $55 + $537 = $592.