In factoring polynomials it's sometimes handy to break up the work graphically. Lisa Nuss, a member of Sam Shah's New Blogger Initiation, shared a handy graphic organizer last week.
I struggle with factoring polynomials, myself, so I wanted to give it a try.
It started out easy.
I started factoring polynomials with 1 as the leading coefficient (i.e. x2 has no messy number in front of it).
I factored: 
First, I put the first and last terms in the boxes. (Note that this graphic organizer works the same way as a multiplication table.)
Then I factored those two in the given “factors” boxes. I determined which factors of 48 would add up to 14, and filled in the chart appropriately.
I was done with that factorization.
Yay me!
Then I got into harder stuff.
Lisa put in an extra "Factors" box to handle non-unit leading coefficients. So I went for a big dog: 
Here's how far I got before the breaks squealed:
Factoring polynomials like this one shouldn't be too much of a problem. Especially if you use a page protector and a dry erase pen to do the trial and error work, as Lisa suggested.
But I don't have such fancy technology.
And I don't like to erase my work. I want to see everything I've tried. For me, it's very likely that I make a mistake and have to go back. And it's a real pain to have to re-create everything.
So instead of playing trial and error with the one big sheet of paper, I created a Factor Trial & Error Boxes worksheet (or in Lisa's terminology: a graphic organizer).
Here's what my work looked like:
(It was a coincidence that the right answer was last, by the way.)
With that info, I could go back to my big graphic organizer and finish the problem.
This was very pleasing. I was able to use Lisa's graphic organizer and mine to make sure I didn't lose any options in my my trial & error.
Will it work for you and your kids? Download the Factor Trial & Error Boxes worksheet now and give it a shot!
|  |  |
You might also like:
- Polynomial Factoring Practice – with YouTube!
- How to Answer “When am I going to use this?”
- How to Use the Quadratic Formula to Never Factor Polynomials Again
- Math Puzzle Inventing – Can You Do It?
This post may contain affiliate links. When you use them, you support us so we can continue to provide free content!
 |
Oo, pick me, pick me!
There's a quick way to find the missing magic numbers -- find the factors of (ac) that add up to (b) -- so for 6x^2 + 65x + 50, you'd look at 300; the possibilities are 1 and 300, 2 and 150, 3 and 100, 4 and 75, 5 and 60 (which works), 6 and 50, 10 and 30, 12 and 25, or 15 and 20.
It's a little bit more work up front, but it saves you doing several grids.
Colin Beveridge recently posted..Quotable maths: Roberts
I think that may be the point, Colin. That method totally works for you (I'm guessing) - but it sends me into panic mode.
My major prof in grad school trained me to "get my hands dirty" (he'd tell me that ALL THE TIME). So now I write every single detail out.
And for our students - whatever works for them, should be what they use.
Thanks for stopping by!
This is an interetsing method… I didn't come accros it before… I like it! Do share more
Cristina recently posted..ThoughtBox wins Blueface Business Elevator Final
Thanks, Cristina! I'll happily pass along things as I find them.