# How to Factor Polynomials on a Graphing Calculator (TI-83 and TI-84)

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## Introduction: How to Factor Polynomials on a Graphing Calculator (TI-83 and TI-84)

These instructions will explain step-by-step on how to factor polynomials on a TI-83/TI-84 graphing calculator

## Step 1:

Begin by selecting the PRGM button and scroll over to NEW, click ENTER and name the program and then click ENTER. Having the name relate to the formula is always a good idea. (Example: Factors)

## Step 2:

Press the PRGM button, scroll once to the right to I/O, scroll down and select ClrHome. Press PRGM again, scroll once to the right to I/O and select Input, then hit 2ND ALPHA and type in “ENTER A:” (use the + to make quotations). After “ENTER A” put a comma followed by the variable A.

## Step 3:

Follow the above instructions to create the same input but with “ENTER B” and “ENTER C” You should have 3 sets of inputs at the end of this step. ex - Input “ENTER B:” , B Press ENTER

## Step 4:

Press MATH, scroll once to the right and select “gcd(“. Press MATH again, scroll right and select “abs(“. In the of the “abs(“ put your variable A and then close the parenthesis. Repeat these steps for the variable B. For variable C all that is needed is “abs” followed by three sets of parenthesis. After the parenthesis press STO,located above the ON button, which is the store button followed by the variable G. Press ENTER

## Step 5:

Select PRGM and select the If statement. Skip a few lines and select a left parenthesis and put the variable G into it. Select 2nd MATH and then select the not equal sign followed by zero and the end of the parenthesis. Press ENTER

## Step 6:

Press PRGM and select the Then statement. Press ENTER

## Step 7:

Begin with a parenthesis on a new line followed by the variable A divided by variable G and end parenthesis. Then STO the answer with variable A. Press ENTER. Repeat these same steps but with variables B and C. ex - (C/G)->C (To store an answer press STO, it will be followed by an arrow then enter the variable as instructed)

## Step 8:

Select PRGM and put End statement after the three above lines in step 7.

## Step 9:

Begin with a parenthesis and put variable A multiplied by C followed by a parenthesis. After the parenthesis STO with variable D. Press ENTER.

## Step 10:

Select 0 and STO it with variable L. Press ENTER.

## Step 11:

Select 1 and STO it with variable J. Press ENTER.

## Step 12:

Select PRGM and select the While statement. Begin a parenthesis followed by variable L does not equal(≠) variable B, end with a parenthesis. Press ENTER. ex - While (L x=B)

## Step 13:

Begin with a parenthesis followed by variable D divided by variable J. End the parenthesis and STO to variable K. Press ENTER.

## Step 14:

Select PRGM and select the If statement. Press the MATH button and scroll once to the right and select fPart( (#4 on the list) followed by a parenthesis then variable K followed by another parenthesis and set that equal to 0 followed by once more parenthesis. ex - If (fPart(K)=0) Press ENTER

## Step 15:

Select PRGM and select Then. Press ENTER.

## Step 16:

Select variable J and add K to STO variable L. Press ENTER. Select variable J and add 1 to STO variable J. Press ENTER.

## Step 17:

Select PRGM and select statement Else. Press ENTER.

## Step 18:

Select variable J and add 1 to it followed by STO variable J. Press ENTER.

## Step 19:

Select PRGM and select statement END. Repeat this once on a new line. Press ENTER.

## Step 20:

Select variable J and subtract by 1 and STO variable J. Press ENTER. Select variable A and STO it to O. Press ENTER.

## Step 21:

Press MATH and scroll once to the right to select gcd( (located at the bottom of NUM) followed by abs( which is located at the same spot. After the parenthesis on abs( follow it with variable K. then put a comma followed by abs( with a 0 in the parenthesis. Add two more parenthesis to finish the statement followed by STO variable H. Press ENTER

## Step 22:

Begin with a parenthesis followed by variable K divided by variable H followed by a parenthesis and STO with variable K. Press ENTER. Begin with a parenthesis followed by variable O divided by H and STO it to O. Press ENTER

## Step 23:

Select gcd( and abs( followed by variable J and end parenthesis. Begin with a comma followed by abs( with variable A followed by two parenthesis and STO it to variable M. Press ENTER.

## Step 24:

Begin with a parenthesis followed by variable J divided by M, end parenthesis and STO it to variable J. Press ENTER. Begin with a parenthesis followed by variable A divided by M, end parenthesis and STO it to variable A.

## Step 25:

Select 2nd 0 which will bring up the CATALOG and select PlotsOff. Press ENTER. Select CATALOG again and select AxesOff. Press ENTER. CATALOG once again and select ClrDraw. Press ENTER.

## Step 26:

This step is for the display of the formula. Select 2nd PRGM and then select Text followed by a parenthesis with the numbers -1,15,0,G,”(,O,”X+”,K,”)(“,A,”X+”,K,”)(“,A,”X+”,J,”)” (You can skip to a new line for each parenthesis to make it cleaner)

## Step 27:

To test program press PRGM (make sure EXEC is highlighted) and scroll to your program name and press ENTER.

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## 2 Questions

0

how do i save before testing,and is there a way to edit the program after creation

1

i am on the last line how do i save before i try it

so after step 26 you press PRGM? cuz it dont work...

2 replies

im not sure what happened cuz now when i press factor it says enter A. what?

A(x^2)+B(x)+C
Ex. x^2 + 5x + 4
A: 1
(x is the same as 1x)
B: 5
C: 4

The program doesn't seem to work if only B is negative, C has to be negative as well. I haven't tested a negative A yet tho.

Is there a way to factor polynomials with variables via calculator? For example: X^2+2X-99

A: 1
(x is the same as 1x)
B:2
C: -99

I just get nothing it never loads past the screen where it says
ENTER A:#
ENTER B:#
ENTER C:#

The program doesn't seem to work if only B is negative, C has to be negative as well. I haven't tested a negative A yet tho.

A little disappointed that I wasted a good portion of my life I won't regain painstakingly inputting this information in my TI-83+ only to have it not work. Once I enter A,B,C all I get is an error break message and after choosing "GoTo" and going back to the formula provided several times and ensuring everything was exactly as presented in the pics provided It still does not work. For step 20, A STO 0 later appears as A STO O in step 21. Is this in error? Is it O or 0?

3 replies

same here. I built this whole thing and it doesn't even work. please help! the error is in step 20 just as MandiH8 said.

It's the letter O, you can't STOre variables into numbers.

It's the letter O, you can't STOre variables into numbers.

thank you so much!!! this makes things much easier

4 replies

What do you input when it asks for a,b, and c?

A(x^2)+B(x)+C
Ex. x^2 + 5x + 4
A: 1
(x is the same as 1x)
B: 5
C: 4

you might have already been told- or deleted the program- but you put in the coefficients A, B, and C according to the formula Ax2 + Bx + C :)

What do you put for a b and c?

Hi everyone, this was a class project me and two other students had to do in college two years ago. I wish I could answer your questions but I'm not the one who came up with this idea. The actual deceloper has no ties to this account anymore. Refer to previous comments to find helpful tips/answers. Good luck!

hi how do i put the equation in

when i press prgm(f)

it comes up prgmF

and then what?

i tried to enter equation and it didn't work (error)