Answer:
$.20 × (x) + $79
Explanation:
To find out how much needs to be paid, subtract the 500 from the total amount of minutes used to find the amount of minutes used over 500. Then, multiply the additional minute cost by the additional minutes and the add the normal price to that.
For example:
Say they used 560 minutes in a month. You would subtract 500 from 560 to get to get 60. Then, you would multiply 60 by $.20 to get $12. Then, add $12 to the original price of $79 to get $91, and that would be the total cost that month.
560 - 500 = 60 × $.20 = $12 + $79 = $91
Hope this helps!