## 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.

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)

please help

Whenever I put any numbers in for A, B, and C i always get syntax error. what should i do

This is a really excellent tutorial and works extremely well 90% of the time. However, if coefficient A or B is negative (assuming the formula Ax2 + Bx + C) the program just keeps loading and loading and eventually crashes. I have a TI-84+ CE, if that makes a difference :)

I have the same issue on a ti 83 plus. it just sits there spinning forever. Any fix?

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

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

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?

It works guys! You just have to be careful with the 0(zeros) and the O(letter). In step 20 he put 0(zero) which should be O(letter), you can notice he corrected the mistake in step 21.

Good Job techno249, you made my life easier!!!

Whenever I go to enter the variables to try out the formula, it does not let me enter C, just A and B. any suggestions?

For those of you experiencing issues with the program, make sure you input O, not 0 starting from step 20, (which by the way the image shows 0, but in the following step, it shows the author correcting the mistake and writing O.) and keep inputing every one of them as O with the exception of the final step in which the first is actually 0, and the following is O.

Hope this helps :3

Wow! This is awesome. This will make a lot of things easier. Thanks!

It works! For those of you wondering about what to input for A, B and C, you just put in the coefficients of the polynomial (Ax² + Bx + C). Make sure to use the appropriate signs!

after i insert the problem how do i get the answer?

Great work! Your instructions are clearly and concisely written and you do a great job of breaking them down into manageable steps. I appreciated having images to accompany each step. A few minor things: I'd recommend doing a careful proofread before your final project is due. There are a few spacing issues, some missing punctuation, etc. I did have a question about Step 3–when you say "follow these instructions," do you mean that readers should go back and repeat the first two steps again? That could be clarified. Also, on Step 26 you say "This last step," but there's actually a Step 27, which some readers might miss if they thought Step 26 was the last. Maybe you mean, "This last programming step" or something like that? Overall, well done.

Thank you for your feedback. We will take these ideas into consideration when rewriting, revising, and editing our instructions.

after i put the program in and then put in a problem for example: 7x^2-6x-13. what do i do to get the answer

Hi Techno249 Can you run the program so we can see what it's suppose to look like. I am having trouble getting this to work. Thanks

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

I entered everything correctly but after I enter my numbers into the A,B,C it just loads and nothing ever appears

Doesn't work ugh!

OH I THINK ITS WORKING I JUST DONT KNOW HOW TO INPUT THE POLYNOMIAL EQUATIONS HELLLPP!! THANK YOU SO MUUCHH

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

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

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?

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.

I just get nothing it never loads past the screen where it says

ENTER A:#

ENTER B:#

ENTER C:#

My TI-83 plus just load with a tiny bar off to the side after I type in my polynomial and it never ends up loading? Please help

i am also having an issue with this, i am trying to factor the polynomial 14y^3+28y^2-54y and i dont know the correct format in which to input, please help, thank you, and great job!

I get a domain error not sure what happened.....

This is absolutely pointless. How do I pt the numbers in there to get the answer? every time I do, I get an error....

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

Interesting. I knew that you could factor them with a TI-89. But I didn't know that you could do it with an 83. Thanks for sharing.

No problem, glad to spread the word. Thanks for stopping by!