Chapter 6 Factoring and Quadratic Equations Section 1













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Chapter 6 Factoring and Quadratic Equations Section 1 An Introduction to Factoring; the Greatest Common Factor; Factoring by Grouping Copyright © 2016, 2012, and 2009 Pearson Education, Inc. 1
Study Strategy Study Groups üUnderstanding Copyright © 2016, 2012, and 2009 Pearson Education, Inc. 2
Concept Greatest Common Factor (GCF) The greatest common factor of two or more integers is the largest whole number that is a factor of each integer. For a variable factor to be included in the GCF, it must be a factor of each term. Copyright © 2016, 2012, and 2009 Pearson Education, Inc. 3
Example Find the GCF of 48 and 54. 1 • The prime factorization of 48 is 24 · 3 and the prime factorization of 54 is 33 · 2. The prime factors that they share 2 and 3, which is the smallest power of each. The GCF is 2 · 3 = 6. Copyright © 2016, 2012, and 2009 Pearson Education, Inc. 4
Example Find the GCF of 384, 420 and 504. 2 The prime factorizations: 384 = 27 · 3 420 = 22 · 3 · 5 · 7 504 = 23 · 32 · 7 The only primes that are factors of all three numbers are 2 and 3. The smallest power of 2 is 22, and the smallest power of 3 is 31. The GCF is 22 · 3 = 12. Copyright © 2016, 2012, and 2009 Pearson Education, Inc. 5
Example Greatest Common Factor (GCF) 3 Find the GCF: GCF of 35, 14, & 49: 7 GCF: Copyright © 2016, 2012, and 2009 Pearson Education, Inc. 6
Concept Factoring Out the Greatest Common Factor The first step for factoring any polynomial is to factor out the GCF of all of the terms. Copyright © 2016, 2012, and 2009 Pearson Education, Inc. 7
Example 4 Factoring Out the Greatest Common Factor out the GCF: Copyright © 2016, 2012, and 2009 Pearson Education, Inc. 8
Example 5 Factoring Out the Greatest Common Factor out the GCF: Copyright © 2016, 2012, and 2009 Pearson Education, Inc. 9
Example Factor GCF. by factoring out the 6 The binomial b + 5 is a common factor for these two terms. Begin by factoring out this common factor. The only factors that remain are a and 8. Copyright © 2016, 2012, and 2009 Pearson Education, Inc. 10
Concept Factoring by Grouping To factor a polynomial with four terms by grouping, we split the polynomial into two groups. We factor a common factor out of the first two terms and another common factor out of the last two terms. If the two “groups” share a common binomial factor, then this binomial can then be factored out to complete the factoring of the polynomial. Copyright © 2016, 2012, and 2009 Pearson Education, Inc. 11
Example 7 Factoring by Grouping Factor by grouping: Copyright © 2016, 2012, and 2009 Pearson Education, Inc. 12
Example 8 Factoring by Grouping Factor by grouping: Copyright © 2016, 2012, and 2009 Pearson Education, Inc. 13