6.2 polynomials and linear factors at the end of this lesson, you should be able to: factor sums...
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6.2 Polynomials and Linear Factors
At the end of this lesson, you should be able to:
Factor sums and differences of cubes Solve a polynomial equation by factoring Write a polynomial function from its zeros
Factoring the Sums and Differences of Cubes
13 = _ 23 = _ 33 = _ 43 = _ 53 = _
63 = _ 73 = _ 83 = _ 93 = _ 103 = _
1 64278
216 512 1000
125
729343
Being familiar with perfect cubes will make cubing binomials and factoring sums and
differences of cubes easier.
Special Factoring Patterns
Sum of Two Cubesu3 + v3 =
Example: u3 + 27 =
Difference of Two Cubesu3 - v3 =
Example: u3 + 64 =
(u + v) (u2 - uv + v2)
(u - v) (u2 + uv + v2)
…more know-by-♥ stuff!
Factor the polynomials:
a. x3 - 27 b. x3 - 64
c. x3 + 125 d. x3 + 216
e. 4x3 + 500 f. 3x 3 - 192
REVIEW: FACTORING BY GROUPING
Factor the polynomials:
a. 4x3 - 6x2 + 10x – 15
b. x3 - 2x2 - 4x + 8
REVIEW: Factoring By Using Combined Methods
Factor the polynomial COMPLETELY:
2x3 + 10x2 + 12X
ZERO PRODUCT PROPERTY
Recall: Let a and b be real numbers. If ab = 0, then a = 0 or b = 0.
Alert!
This property connects factoring to solving equations!
SOLVING POLYNOMIAL EQUATIONS BY FACTORING
Solve the following equations by factoring:
a. 3x4 = 48x2 b. x3 - 216 c. 5x3 + 135
FACTOR THEOREM
The expression x – a is a linear factor of a polynomial if and only if the value a is a zero of the polynomial function.
You can reverse the process and write the linear factors when you know the zeros (solutions). The relationship between the linear factors of a polynomial and the zeros of a polynomial is given by the Factor Theorem.
Write the factors of a polynomial whose zeros are 2, 2, & -3.
WRITING A POLYNOMIAL FUNCTION FROM ITS ZEROS
Alert!
A repeated zero is called a multiple zero. A multiple zero has a multiplicity equal to the number of times the zero occurs.
What is the multiplicity of the polynomial function? Explain.
Final Checks for Understanding
Given x3 - 4x2 = - 4x, determine the following:
Factors:
__________________
Solutions:
__________________
X-intercepts:
__________________
Zeros: __________________
Homework
Connections: Zeros, Factors, and Solutions WS, plus text_______________