Question 148099: Factor: x^2+3x+2 and 72-22x+x2
I dont really understand how to factor it. Could someone maybe please explain it to me?
Answer by mangopeeler07(462)   (Show Source):
You can put this solution on YOUR website! I will explain. whenever the  term has a coefficient of 1, you start with (x )(x ).
in  , everything is positive, so add two addition signs.
(x+ )(x+ ).
Then, find the factors of 2 that add up to 3. That would be 2 and 1. Put them in there.
 . You're done.
In  , first reorder it to  . Then you start with
(x )(x ).
everything is not positive, only the first and last, so you add two subtraction signs.
(x- )(x- ).
Then find the two factors of 72 that would add up to 22. That would be 18 and 4. So put them in there.
 . You're done.
If you want to check them, I would just use the acronym I came up with called SAM. That stands for Squared, Add, Multiply. And it's easy to remember, especially if your name is Sam. Anyway, here's how it works:
Start with:
(x+2)(x+1) and (x-4)(x-18)
Then do your SQUARED terms:
(x+2)(x+1) and (x-4)(x-18)
and
Then ADD your other two numbers (keeping in mind the negatives) and attach the variable:
(x+2)(x+1) and (x-4)(x-18)
 and 
Then MULTIPLY the last two numbers (keeping in mind the negatives):
(x+2)(x+1) and (x-4)(x-18)
and
So now you know how to factor it and how to check your answer!
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