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Objectives The student will be able to: MFCR Ch. 4-4 GCF and Factoring by Grouping 1-7-14. 1. find the greatest common factor (GCF) for a set of monomials. The Greatest Common Factor (GCF) of 2 or more numbers is. the largest number that can divide into all of the numbers.
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ObjectivesThe student will be able to:MFCR Ch. 4-4 GCF and Factoring by Grouping 1-7-14 1. find the greatest common factor (GCF) for a set of monomials.
The Greatest Common Factor (GCF)of 2 or more numbers is the largest number that can divide into all of the numbers. 4) Find the GCF of 42 and 60.
4) Find the GCF of 42 and 60. • = 2 • 3 • 7 • 60 = 2 • 2 • 3 • 5 What prime factors do the numbers have in common? Multiply those numbers. The GCF is 2 • 3 = 6 6 is the largest number that can go into 42 and 60!
5) Find the GCF of 40a2b and 48ab4. 40a2b = 2 • 2 • 2 • 5 • a • a • b 48ab4 = 2 • 2 • 2 • 2 • 3 • a • b • b • b • b What do they have in common? Multiply the factors together. GCF = 8ab
What is the GCF of 48 and 64? • 2 • 4 • 8 • 16
ObjectivesThe student will be able to: Factor using the greatest common factor (GCF).
Review: What is the GCF of 25a2 and 15a? 5a Let’s go one step further… 1) FACTOR 25a2 + 15a. Find the GCF and divide each term 25a2 + 15a = 5a( ___ + ___ ) Check your answer by distributing. 5a 3
Find the GCF 6x2 Divide each term by the GCF 18x2 - 12x3 = 6x2( ___ - ___ ) Check your answer by distributing. 2) Factor 18x2 - 12x3. 3 2x
3) Factor 28a2b + 56abc2. GCF = 28ab Divide each term by the GCF 28a2b + 56abc2 = 28ab ( ___ + ___ ) Check your answer by distributing. 28ab(a + 2c2) a 2c2
Factor 20x2 - 24xy • x(20 – 24y) • 2x(10x – 12y) • 4(5x2 – 6xy) • 4x(5x – 6y)
5) Factor 28a2 + 21b - 35b2c2 GCF = 7 Divide each term by the GCF 28a2 + 21b - 35b2c2 = 7 ( ___ + ___ - ____ ) Check your answer by distributing. 7(4a2 + 3b – 5b2c2) 4a2 3b 5b2c2
Factor 16xy2 - 24y2z + 40y2 • 2y2(8x – 12z + 20) • 4y2(4x – 6z + 10) • 8y2(2x - 3z + 5) • 8xy2z(2 – 3 + 5)
ObjectiveThe student will be able to: use grouping to factor polynomials with four terms.
Factoring ChartThis chart will help you to determine which method of factoring to use.TypeNumber of Terms 1. GCF 2 or more 2. Grouping 4
1. Factor 12ac + 21ad + 8bc + 14bd Do you have a GCF for all 4 terms? No Group the first 2 terms and the last 2 terms. (12ac + 21ad) + (8bc + 14bd) Find the GCF of each group. 3a (4c + 7d) + 2b(4c + 7d) The parentheses are the same! (3a + 2b)(4c + 7d)
2. Factor rx + 2ry + kx + 2ky Check for a GCF: None You have 4 terms - try factoring by grouping. (rx + 2ry) + (kx + 2ky) Find the GCF of each group. r(x + 2y) + k(x + 2y) The parentheses are the same! (r + k)(x + 2y)
3. Factor 2x2 - 3xz - 2xy + 3yz Check for a GCF: None Factor by grouping. Keep a + between the groups. (2x2 - 3xz) + (- 2xy + 3yz) Find the GCF of each group. x(2x – 3z) + y(- 2x + 3z) The signs are opposite in the parentheses! Keep-change-change! x(2x - 3x) - y(2x - 3z) (x - y)(2x - 3z)
4. Factor 16k3 - 4k2p2 - 28kp + 7p3 Check for a GCF: None Factor by grouping. Keep a + between the groups. (16k3 - 4k2p2 ) + (-28kp + 7p3) Find the GCF of each group. 4k2(4k - p2) + 7p(-4k + p2) The signs are opposite in the parentheses! Keep-change-change! 4k2(4k - p2) - 7p(4k - p2) (4k2 - 7p)(4k - p2)