Adding Polynomials
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Alph0005.gif (2155 bytes)dd like terms by adding the numerical portion of the terms, following the rules for adding signed numbers.
(The numerical portion of an expression is called the coefficient.)

 

Example:  Add:  (2x2 - 4) + (x2 + 3x - 3)

 
Below are several different ways to attack this example:

 1. Using a horizontal method to add like terms:

 Remove parentheses.   Identify like terms.  Group the like terms together.
Add the like terms.

 

(2x2 - 4) + (x2 + 3x - 3)  

 

= 2x2 - 4 + x2 + 3x - 3 .. identify like terms
 

= 2x2 + x2 + 3x - 4 - 3

.. group the like terms together

 

= 3x2 + 3x - 7

... add the like terms


 

 2.  Using a vertical method to add like terms:

Arrange the like terms so that they are lined up under one another in vertical columns, adding 0 place holders if necessary.   Add the like terms in each column following the rules for adding signed numbers.

2x2  +  0x - 4
+ x2  +  3x - 3   
Line.gif (926 bytes)
3x2 + 3x - 7


 

 3. Using algebra tiles to add like terms:

Key:

Sp_add13.jpg

= x² Sp_add14.jpg Sp_add15.jpg

(2x2 - 4) + (x2 + 3x - 3)

Saddh2.gif


 

4.  Using the Distributive Property to add like terms:

When you are adding the coefficients (the numbers in front of the variables) of like terms together, you are actually using the distributive property in reverse. 

4x2 + 5x2 = (4 + 5) x2 = 9x2