Algebra Review - Multiplying Polynomials

1. Multiplying (x + y) and (x - y)

This is the basic way to do it.

Use a method called FOIL. First multiply the first terms, which are x and x and you get x2. Then multiply the outside terms, which is the first x and the last y to get -xy. Then multiply the inside terms, which is the first y and the second x to get yx or xy. Lastly, multiply the last terms, which is y and y to get -y2. Then add everything together: x2 + (-xy) + xy + (-y2) = x2 - y2.

So remember the basic rule: .


2. More Binomial Multiplication

Here are some basic examples:


3. Exponents and Products

5 5 5 5 = 54
x x x x x x = x6
(-y)(-y) = (-y)2

And so on.

Memorize the following rule. When you multiply powers where the base (the big size number) are the same, you just add the exponents:

Some examples:

3. Multiplying Polynomials and Monomials

To multiply the following, just multiply the outside term with the first term, then the second term. The examples should be enough for you to understand.


4. Squaring Binomials

Another basic rule to remember when squaring this: (x + y)2

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