The answer is:
[tex]WatchCost=StartingBalance-EndingBalance\\\\WatchCost=515.50-496.11=19.39[/tex]
The cost of the watch is $19.39.
To solve the problem, we can create a linear equation using the given information about the starting balance and the ending balance.
We know that the starting balance was $515.50, and then, after writing a check to buy the watch, the balance was $496.11, so, writing the function we have:
[tex]WatchCost=StartingBalance-EndingBalance\\\\WatchCost=515.50-496.11=19.39[/tex]
Hence, we have that the cost of the watch is $19.39.
Have a nice day!