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### Factoring Rules

```
Date: 6/28/96 at 14:58:57
From: Anonymous
Subject: Factoring Rules

Dear Dr. Math.

to finding the answer was so clear that I've been wondering if there
is a clear set of factoring rules or procedures that would help me
with these difficult factoring exercises. I'll be going into 9th grade
next September.

Thank you.
Jackie
```

```
Date: 6/28/96 at 17:44:11
From: Doctor Gary
Subject: Re: Factoring Rules

Factoring will always be more art than skill (although there are
algorithms which will permit you to factor quadratic or cubic
expressions, the former being much easier than the latter).

The best way to improve your skill at factoring is to do some
multiplying.  For example, when you multiply (x+2) by (x-3), you'll
notice that the product has a term of x^2, a term of -6 and a third,
composite, term of (2-3)x.

More generally, whenever, you multiply (x+m) by (x+n), the product
will have a term of x^2, a term of mn and a composite term of (m+n)x.

When the time comes that you have to factor something like:

x^2 -3x -10,

you'll know to be thinking in terms of some "m" and "n" such that mn
is equal to -10 and (m+n) is equal to -3.

Good luck, and happy factoring.

-Doctor Gary,  The Math Forum
Check out our web site!  http://mathforum.org/dr.math/
```
Associated Topics:
Middle School Factoring Expressions

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