If f(x) is a polynomial and f(a) = 0, then (x–a) is a factor of f(x) Proof of the factor theorem Let's start with an example Consider 4 8 5
The Factor Theorem: Suppose p is a nonzero polynomial It is important to note that it works only for these kinds of divisors 5 Also Example 3 2 1
Now consider another example of a cubic polynomial divided by a linear divisor From the above example, we can deduce that: 2 ? 3 + 4 + 5 =
1 Factorise polynomial expressions 2 3 2 Divide a polynomial by a linear or quadratic factor 2 3 3 Apply the remainder theorem 2 3 4 Apply the factor theorem
For example, the zeros of p are –3, 1, and 5, and the factors of p(x) are x + 3, x - 1, and x - 5 The following theorem generalizes this relationship
2 Remainder and Factor Theorems Interactive Mathematics Factor theorem state with proof examples and solutions factorise the Polynomials Maths Mutt
Example 8: 7 5 4 3)( 2 3 + ? + = x x x xf Find )4( ? f using (a) synthetic division (b) the Remainder Theorem Example 9: Solve the equation
4 2 - Algebra - Solving Equations 4 2 8 - The Factor Theorem Higher Level ONLY 1 / 5 Example 1 Q Suppose f (x)=5x3 - 14x2 + 12x - 3
24 fév 2015 · Use long division to determine the other factors Page 6 6 February 24, 2015 Example Five Factor fully
PROBLEM You Have the Right to the Remainder Theorem Chapter 5 Polynomial Expressions and Equations example are correct? - Long Division
linear factors corresponding to the zeros x=1,2 and 4 That is, Proof of the factor theorem Let's start with an example Consider 4 8 5 2 16 4 18 4 32 8 36
xf Example 8: 7 5 4 3)( 2 3 + − + = x x x xf Find )4( − f using (a) synthetic division (b) the Remainder Theorem Example 9: Solve the equation 06 11 3
The Remainder Theorem: Suppose p is a polynomial of degree at least 1 Now take the 2 from the divisor times the 6 to get 12, and add it to the -5 to get 7 The next example pulls together all of the concepts discussed in this section
polynomial division Example 1 Divide 14 5 4 2 3
p Use polynomial division in real-life problems 6 5 5 3 2 2 6 1 1 3 9 Your Notes REMAINDER THEOREM If a polynomial f(x) is divided by x
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101353_6Alg2_6_5.pdf
The Remainder and Factor
Theorems
GoalspDivide polynomials and relate the result to the remainder theorem and the factor theorem. pUse polynomial division in real-life problems. 6.5
VOCABULARY
Polynomial long divisionA method used to divide
polynomials similar to the way you divide numbers
Synthetic divisionA method used to divide a
polynomial by an expression of the form x?k
Your Notes
Divide 4x
4 ?x 2 ?18x?8 by x 2 ?2x?3. Write division in the same format you would use when dividing numbers. Include a 0 as the coefficient of x 3 . x 2 ?2x?3?4?x 4 ???0?x 3 ???1?2?x 2 ???1?8?x???8?
Write the result as follows.
?4x 2 ?8x?3 ? 1 ?? x 2 ?2x?3 4x 4 ?x 2 ?18x?8 ??? x 2 ?2x?3 3x 2 ? x 2 ?8x 3 ? x 2 4x 4 ? x 2
Example 1Using Polynomial Long Division
4x 4 ?8x 3 ?12x 2 ?8x 3 ?13x 2 ?18x ?8x 3 ?16x 2 ?24x 4x 2 ?8x?3 3x 2 ?6x?8 3x 2 ?6x?9 ?1
136Algebra 2 Notetaking Guide Chapter 6
Divide x
3 ?x 2 ?5x?3 by x?2.
Solution
To find the value of k, rewrite the divisor in the form x?k.
Because x?2 ?x?(?2),k? 2.
? x 2 ?x?3 ? 9 ? x ? 2 x 3 ?x 2 ?5x?3 ??? x?2 ?211?53 ?226
1?1?39
Your Notes
REMAINDER THEOREM
If a polynomial f(x) is divided by x?k, the remainder is r?f(k).
Example 2Using Synthetic Division
Factor f(x) ? x
3 ?19x?30 given that f(5) ? 0.
Solution
Because f(5) ?0, you know that x?5is a factor of f(x).
Use synthetic division to find the other factors.
The result gives the coefficients of the quotient. x 3 ?19x?30 ?( x?5 )( x 2 ?5x?6 ) ?( x?5 )( x?2 )( x?3 )
510?19?30
52530
15 6 0
FACTOR THEOREM
A polynomial f(x) has a factor x?kif and only if f(k) ?0.
Example 3Factoring a Polynomial
Lesson 6.5 Algebra 2 Notetaking Guide137
A zero of f(x) ?x
3 ?x 2 ?4x?4 is x??1. Find the other zeros.
Solution
Because f(?1) ?0, you know that x?1is a factor of f(x).
Use synthetic division to find the other factors.
The result gives the coefficients of the quotient. f(x) ?x 3 ?x 2 ?4x?4 ?( x?1)( x 2 ?4) ?( x?1)( x?2)( x?2) By the factor theorem, the zeros of fare ?1,?2, and 2 . ?111?4?4 ?104 10?40
Your Notes
Example 4Finding Zeros of a Polynomial Function
CheckpointComplete the following exercises.
1.Use long division to divide x
2 ?4x?1 by x?3. x?1 ?
2.Use synthetic division to divide 2x
3 ?x 2 ?3x?4 by x?1. 2x 2 ?3x? 6 ?
3.Factor f(x) ?2x
3 ?x 2 ?25x?12 given that f(4) ?0. (x?4)(x?3)(2x?1)
4.A zero of f(x) ?x
4 ? 5x 2 ?4 is 1. Find the other zeros. ?1, ?2, 2 ?2 ? x?1 ?4 ? x?3
Homework
138Algebra 2 Notetaking Guide Chapter 6
Factor Theorem Documents PDF, PPT , Doc