Answer:
Service charge is $3 per month.
Step-by-step explanation:
I'm assuming y is the service charge, and the 12 represents months in a year (how much you pay in a year). This means that this equation finds out how much you pay in a year, to find how much per month, divide the whole thing by 12. Now, we have 25+y = 28. Let's subtract 25 from both sides. This gets us y=3. If y is the service charge, that means the service charge is $3 per month.