# Solving Linear Equations Using a TI-89

Before you begin, clear all previously saved variables and
functions , set the graph mode and

viewing window.

**To Clear Home Screen
**(

**Home**if not on home screen)

**F1**then

**8**

**To Clear Previously Saved Variables**

2

2

^{nd}**F6**then

**Enter Enter**

**To Clear Previously Saved Functions**

Diamond Y=

Diamond Y=

**F1**then

**8 Enter**

**To Set Graph Mode**

Mode(Graph is highlighted)

Mode

→ then

**1**(Function)

**Enter**

**To Set Graph Scale**

Diamond Window

F2: Zoom

6: ZoomStd

F2: Zoom

5: ZoomSqr

Diamond Window

F2: Zoom

6: ZoomStd

F2: Zoom

5: ZoomSqr

Solve : 4(x − 3) − x = x − 6 |

**There are two ways to solve a linear equation
graphically: Using Root and Using
Intersection**

**Graphically: Using Zero (Root)**

Rewrite the equation with 0 on one side .

4(x − 3) − x − x + 6 = 0

Let Y1 equal the left side of the equation.

**Diamond Y=
**Y1 = 4(x − 3) − x − x + 6

Then graph.

**Diamond Graph**

Find the x- intercept (zero)

**F5: Math**

2: Zero

Lower Bound ?: - move cursor to the left of the x intercept using the left or right arrows

2: Zero

Lower Bound ?

**Enter**

Upper Bound?: - move cursor to the right of the x intercept using the right arrow

Upper Bound?

**Enter**

At the bottom of the screen, it shows the x and y coordinate of the x intercept . (3, 0)

**x=3 is the solution to the equation .**

**Graphically: Using Intersection
**

Each side of the equation represents a linear expression . If both sides of the equation are

graphed, their point of intersection has the same y value . Therefore, the x- coordinate of the

point of intersection represents the solution to the equation.

Graph both linear expressions :

**Diamond Y=**

(Clear functions)

Y1 = 4(x − 3) − x

Y2 = x − 6

**Diamond Graph**

To find the point of intersection:

**F5: Math**

5 Intersection

1(The cursor should be blinking on one line and the equation number will

5 Intersection

1

^{st}Curve:appear in the upper right hand corner of the window. If you can’t see the cursor, use the

left or right arrows to bring it into view.)

**Enter**

2(The cursor should move to the next line and the number will change to 2)

2

^{nd}Curve:**Enter**

Lower Bound?:- move cursor to the left of the intersection using the right or left arrow

Lower Bound?:

keys

**Enter**

Upper Bound?:- move cursor to the right of the intersection using the right arrow key

Upper Bound?:

**Enter**

At the bottom of the screen, it shows the x and y coordinate of the point of intersection. (3, -3)

**x=3 is the solution to the equation.**

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