The first plan has $14 monthly fee and charges an additional $.14 for each minute of calls. The seco

The first plan has $14 monthly fee and charges an additional $.14 for each minute of calls. The second plan had a $21 monthly fee and charges an additional $.10 for each minute of calls. For how many minutes of calls will the cost of the two plans be equal?

Set up the cost equation C(m) for the first plan, where m is the amount of minutes you use
C(m) = 0.14m + 14

Set up the cost equation C(m) for the second plan, where m is the amount of minutes you use
C(m) = 0.10m + 21

Set them equal to each other:
0.14m + 14 = 0.10m + 21

Typing this equation into our search engine, we get:
m = 175