<h2>
Hello!</h2>
The answer is:
The cost of the watch is $19.39.
<h2>
Why?</h2>
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:
Hence, we have that the cost of the watch is $19.39.
Have a nice day!