The equation for the monthly charge $y$ in terms of $x$, the number of kilowatt-hours used, is:

$y = 0.0738x + 17.32$

Let me know if you'd like further details or explanations! Here are some related questions:

1. How would the equation change if the base charge increased?
2. What happens to the monthly charge if no kilowatt-hours are used?
3. How would you calculate the cost for 500 kilowatt-hours used?
4. How would this equation change if the charge per kilowatt-hour was in dollars instead of cents?
5. Can this equation be modeled as a linear function?

Tip: Always make sure the units in the equation are consistent before solving or interpreting it!