# TI-89 WORKSHEET 5:Algebra Concepts

The TI-89 can graph many different types of

equations. The following four examples

illustrate different types of equations graphed

on the TI-89. In these examples, the function

must be rewritten to be a function of x. The

examples demonstrate how to use the solve

feature of the calculator to rewrite the function

before graphing.

**Example 1:**

Graph the following equation.

3y – 9x = 15

First, change from standard form to slope-intercept

form by using the solve function :

** Step 1: **Press „ followed by 1 to access the

“solve(” function and press ¸.

**Step 2:** Type in the above equation and then

push the enter key. ¸.

**Step 3:**
Enter the above equation into the

y -editor for y1=. (If you know how to copy and

paste, this process can be simplified )

**Step 4:**
Check for an appropriate viewing

window to graph the equation.

You may also consider using the F2 ZOOM tab on

the top of the y-editor screen:
and

then type
(alpha =) or press
and scroll

down to option A: in order to select “ZoomFit”,

which establishes a window of best fit for viewing

the graph.

Choosing the “ZoomFit” option will automatically

take you to the graph. Therefore, step 5 is only

necessary to go directly from the y-editor to the

graphing screen.

**Step 5:**
Graph the equation.

**Example 2:** Graph the following equation

y = x^{2} + 2x − 4

**Step 1:**
Enter the above equation into the

y-editor for y2=.

**Step 2: **Highlight y1 and press
This will

remove the check mark and instruct the

calculator to only graph y2.

Step 3: Graph the equation.

**Example 3: **Graph the following equation

First, this must be written as a function of x.

Therefore it must be solved for y .

**Step 1:** From the home screen select

**Step 2: **Type in the equation. Type in a

comma and then a y. Finish by typing a close

parenthesis and press enter.

**Step 3: **Use your arrow keys to highlight the

answer. Press
to copy the answer.

**Step 4: **Press
to access the equation

editor screen. Using
paste the

answer in y1. The answer will appear in the

entry line . It is important that the extra y= is

deleted before you hit enter.

**Step 5:**
Graph the equation.

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