Melanie and Colby have different phone services.
The relationship of the monthly cost, y, and the text
messages sent, x, is a linear function. The cost of
Colby's plan is y=0.30x+5. The cost of Melanie's
plan is shown in the table below.
Texts (x)
5
100
Cost(y)
2.50
2.
5.00
15
7.50
20
10