The equation y = 0.1x + 50 gives the monthy cost of a cell phone plan where x is the number of text messages sent and received. what is the cost of your phone plan if you sent and received 315 text messages

You are given the function where x is the number of text messages sent and received and y is the monthy cost of a cell phone plan.

So if you sent and received 315 text messages, then x= 315 and you have to find y. With this aim simply substitute x=315 into the function expression:

the cost of your phone plan is  81.5.

333.74 ! should be your answer for this question