Fundamentals of Math

Fundamentals of Mathematics

Graphing: Table Method Of course, the table only shows some of the possible monthly costs; there are many more combinations. Rather than attempt to manually write every possible combination, it is often quicker (and easier) to graph the relationship.

Minutes Used ( ) Total Cost ( )

Order Pairs

Graph

→

0 minutes

$15.00

(0,15)

(1,15.25)

→

1 minute

$15.25

(2,15.50)

→

2 minutes

$15.50

(3,15.75)

→

3 minutes

$15.75

(4,16)

→

4 minutes

$16.00

(5,16.25)

→

5 minutes

$16.25

The graph shows all possible solutions. To determine the cost at x-minutes, locate the -value on the -axis. Then look up (or down) to find your line and determine the corresponding -value. For example, based on the graph, we can see that if we talked for 1.5 hours (or 90-minutes), then the monthly cost on this cellphone plan would be $37.50.

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