# Factoring Polynomial

1. Mar 20, 2013

### ForwardDrift

Hey,

This isn't really a homework question, per se, as I am relearning some pre calculus for kicks. But I figured his would be the place to ask. For whatever reason, this very simply factoring issue has got my head spinning. I'm not exactly sure what I am doing wrong to factor this equation completely.

1. The problem statement, all variables and given/known data

[(x-1)(x+2)2 - (x-1)2(x+2)]

2. Relevant equations

n/a

3. The attempt at a solution

So here is what I did (though I am sure incorrectly) so far. I have not clue what to do after that.

[(x-1)(x+2)2 - (x-1)2(x+2)]

[(x-1)(x+2)(x-2) - (x-1)(x-1)(x+2)]

And then ??????

-ForwardDrift

Last edited: Mar 20, 2013
2. Mar 20, 2013

### SammyS

Staff Emeritus
Hello ForwardDrift. Welcome to PF !

What factor(s) is(are) common to (x-1)(x+2)(x-2) and (x-1)(x-1)(x+2) ?

Factor it (them) out.

Whatever remains should be combined.

3. Mar 20, 2013

### ForwardDrift

Thanks, I'm glad to be on physics forum SammyS!

Note: I realized the second (x-2) in my post should have been a (x+2), instead....

So this is what I ended up doing...

(x-1)(x+2)(x+2) - (x-1)(x-1)(x+2)

(x+2)(x-1) [ (x - 1) - ( x + 2) ]

(x+2)(x-1) [ 3]

3(x+2)(x-1)

Is this right, Sammy? I'm not sure about that 3. Something seems wrong about the way I calculated the inside brackets. Am I supposed to reverse a (-) or (+) inside the brackets or something?

-ForwardDrift

Last edited: Mar 20, 2013
4. Mar 20, 2013

### SammyS

Staff Emeritus
Not quite.

[ (x - 1) - ( x + 2) ] = [ x - 1 -x -2 ] = -3

5. Mar 20, 2013

### ForwardDrift

Alright, thanks Sam, my man. You have been a great help! :)