Use a graphing utility to numerically or graphically verify your work in any one exercise from Exercises 9–12. For assistance on how to do this, refer to the Technology box on page 129.

The Technology box

Data from Exercise 9

You are choosing between two health clubs. Club A offers membership for a fee of $40 plus a monthly fee of $25. Club B offers membership for a fee of $15 plus a monthly fee of $30. After how many months will the total cost at each health club be the same? What will be the total cost for each club?

Numeric and Graphic Connections We can use a graphing utility to numerically or graphically verify our work in Example 3. Numeric Check Display a table for y and y. When x= 10, y, and y have the same value, 70. With 10 bridge crossings, costs are the same, $70, for both options. 2 4 X 6 8 10 12 14 16 18 20 22 X=10 Y 14 28 42 56 70 84 98 112 126 140 154 Y 38 46 54 62 70 78 86 54 102 110 118 The monthly cost without the discount pass 7x Enter y = 7x. must equal = the monthly cost with the discount pass. 30 + 4x Enter y = 30 + 4x. Graphic Check Display graphs for y and y2. Use the intersection feature. Y = 7x Y2=30+4X Y2 = 30 + 4x Intersection Y=70 [0, 20, 2] by [0, 150, 5] X=10 Graphs intersect at (10, 70). With 10 bridge crossings, costs are the same, $70, for both options.