Answer:
Draw a graph which joins the points (100, 135) and (500, 375) and has a slope = 0.6
The ordered pairs are: (100, 135) and (500, 375)
The first number is the number of minutes of usage and the second number is the charge of the month.
The slope is: ( 375 -135) / (500 - 100) = 240/400 = 0.6
Explanation: