Adding and Subtracting Polynomials
After studying this lesson, you will be able to:
 Add and subtract polynomials.
When adding and subtracting polynomials, remember that you can
only add or subtract like terms. And, remember to add or subtract
the coefficients  the exponents do not change.
Example 1
( 3y^{ 2} + 5y  6 ) + (7y^{ 2}  9 )
We are adding two polynomials so all we do is to collect like
terms. It's a good idea to put the answer in descending order as
we go.
Adding like terms the answer will be: 10y^{ 2} + 5y 
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Example 2
( 4x^{ 2} 3y^{ 2} + 5xy )  ( 8xy + 6x^{ 2}
+ 3y^{ 2} )
We are subtracting two polynomials so first we "add the
opposite" in the second polynomial.
This will give us: ( 4x^{ 2} 3y^{ 2} + 5xy )
+ (  8xy  6x^{ 2}  3y^{ 2} )
Now, we add like terms, beginning with the highest exponent so
that our answer will be in descending order. Adding like terms
the answer will be: 2x^{ 2}  3xy  6y^{ 2}
