# Y-Intercept in Color

Using the Casio CFX-9850G Color Graphing Calculator Using to discover
the relationship of the y-intercept and the graph of a line.

Materials: Casio CFX 9850G Graphing Calculator

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This is an excellent lesson for the beginning graphing calculator students
as well as experienced users. The lesson enables the student to discover
the relationship between the y-intercept and B in the equation y=mx+b. The
lesson can also be done using the dynamic graphing function, see
Y-Intercept using Dynamic Graphing.

Y-Intercept in Color

Select graph icon (5)

Set your graphing window to the initial setting.

(CFX-9850G)Shift F3 (to set graph window to initial setting)
INIT (F1) setting the graph window
-6.3 < X < 6.3
-3.1 < Y < 3.1

Graph these 3 equations

Y1 = 2X - 3
Leave this equation in blue
Y2 = 2X + 1
Highlight this equation and make it orange

Have students compare the blue equation and the orange equation.

What things are alike?
What things are different?

Graph and get a blue equation and an orange equation

What things are alike?
What things are different?

Y3 = 2X + 2.5

Highlight the equation and make it green
Compare the green, blue, and orange equations

What things are alike?
What things are different?

Compare the green, blue and orange graphs

What things are alike?
What things are different?

What do you conclude about the impact of the -3, +1, and +2.5?

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Submitted by Dr. Doug Brumbaugh, University of Central Florida.