Answer:
5
Step-by-step explanation:
The equation says y equals 5. I attached a graph below:
Ok so we know he used over 700 because he was charged more than 40. Then we take the $8.10 and divide 0.45 into it. This then gives you 18 more minutes. Then add 18 to 700 and you get 718 min.
Explanation is in the file
tinyurl.com/wpazsebu
Its (-10,-4) because when you graph it you get (-10,-4) straight through the orgin