Sharp EL-9900 operation manual Basic Graphing Features Basic Keyboard, = 3.5 +

Chapter 4

Basic Graphing Features

— Basic Keyboard

This chapter takes the knowledge you have gained in Chapter 3 several steps further.

Note: To try the examples in this chapter, it is required that the Basic Keyboard is already set up by the user. To learn how to set up the Basic Keyboard, read “Changing the Keyboard” in Chapter 1.

1. Try it!

There are two taxi cab companies in your city, Tomato Cab and Orange Cab, with different fare systems. The Tomato Cab charges $2.00 upon entering the taxi cab, and $1.80 for each mile the taxi travels. The Orange Cab, on the other hand, charges $3.50 plus $1.20 per mile. This means that taking the Tomato Cab will initially cost less than

going with the Orange Cab, but will be more expensive as you travel longer distances.

Suppose you need to go to a place 3 miles away from where you are now. Which cab company should you take to save money?

Two math expressions can be derived from the above fare systems. If “y” represents the cost, while “x” represents the mileage, then:

y = 2 + 1.8x	Tomato Cab’s fare system
y = 3.5 + 1.2x	Orange Cab’s fare system

Use the calculator’s graphing capabilities to figure out the approximate point where the Orange Cab gets ahead of the Tomato Cab, in terms of cost performance.

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