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Department of Mathematics
Pindling
Basic Algebra  
by Example
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0.4 Polynomials

Key Concept: Know the basic meaning and properties of a polynomial so as to perform basic operations with
polynomials

Skills to Learn

1. Know how to identify polynomials (monomials, binomials, and trinomials)

2. Know how to add and subtract polynomials

3. Know how to multiply and divide polynomials

4. Know how to find the Conjugate Binomials

Definitions of Polynomials

Polynomials

(a monomial or the sum of monomials)

with whole number exponents

Monomials

(a product of one or more variables)

Binomials

(a polynomial with 2 terms)

Trinomials

(a polynomial with 3 terms)

-5x3 (degree 3, coefficient -5)

2x5 + 3x2

(degree is 5)

2x5y2 + 3x2 + 5x

(degree is 7)

15x3y (degree 4, coefficient 15)

-3x3 - 4y4

(degree is 4)

(degree is 5)

3a2bc2 (degree 5, coefficient 3)

3x2y4 + 3xy

(degree is 6)

3x2y2 + 5xy2 + 2x

(degree is 4)

Add and Subtract Polynomials

Example: Add

Remove parentheses and group like terms

Example: Add

Remove parentheses and group like terms

Example: Subtract

Remove parentheses and group like terms

Example: Subtract

Remove parentheses and group like terms

Multiply Polynomials

Foil method of multiplication

(a + b)(c + d) = ac +ad +bc +bd

Example: Multiply

Remove parentheses and use commutative property

Example: Multiply

Expand (distributive property)

(no like term so finish)

Example: Multiply

Foil

(then combine xy terms)

(then factor out 2)

Example: Multiply

Foil

Dividing Polynomials

Example:

Divide

Move exponents in denominator to numerator

Example:

Divide

Example: (text book gives better example using sign)

Note:

So

Note:

So

Answer is

Example: (text book gives better example using sign)

Note:

So

Note:

So

Answer is

Conjugate Binomials

The conjugate binomial: the conjugate of (a + b) = (a - b) and the conjugate of

(a - b) is (a + b)

Example: the conjugate of

Used to rationalize denominators (also numerators)

Conjugate Binomial

Example: Rationalize

The conjugate of and

So

So

Example: Rationalize denominator for

Conjugate of

So

Example: Rationalize the numerator

Conjugate:

So

So

Example: Rationalize the denominator

Conjugate of

So

Or