#### Answer

4.52+.12x=c, where x= number of minutes used and c= total cost per month.
When 250 minutes are used in one month, the cost for that month is $34.52.

#### Work Step by Step

Every month there is a service fee of 4.52 dollars, which is kept constant. In order to find the cost for the number of minutes used, you must multiply the cost per minute by the number of minutes used. This relationship of minutes and cost can be shown by the expression .12$\times$x. In this case, x= the total number of minutes used in one month. To find the total cost for one month, one must add the constant fee, plus the cost of the number of minutes used.