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Chapter 5. Factoring Polynomials. 5-1 Factoring Integers. Factors - integers that are multiplied together to produce a product. 4 x5 = 20. 2,3,5,7,11,13,17,19,23,29. Prime number - is an integer greater than 1 that has no positive integral factor other than itself and 1.
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Chapter 5 Factoring Polynomials
5-1 Factoring Integers Factors - integers that are multiplied together to produce a product. 4 x5 = 20
2,3,5,7,11,13,17,19,23,29 Prime number - is an integer greater than 1 that has no positive integral factor other than itself and 1.
PRIME FACTORIZATION Prime factorization of 36 36 = 2 x 18 = 2 x 2 x 9 = 2 x 2 x 3 x 3 = 22 x 32
GREATEST COMMON FACTOR The greatest integer that is a factor of all the given integers.
GREATEST COMMON FACTOR Find the GCF of 25 and 100 25 = 5 x 5 100 = 2 x 2 x 5 x 5 GCF = 5 x 5 = 25
Property of Quotients If a, b, c and d are real numbers, then ac =a • c bd b • d
Simplifying Fractions If b, c and d are real numbers, then bc =c bd d
Rule of Exponents for Division If a is a nonzero real number and m and n are positive integers, and m > n, then am= am-n an
Rule of Exponents for Division If a is a nonzero real number and m and n are positive integers, and n > m; then am= 1 an an-m
Rule of Exponents for Division If a is a nonzero real number and m and n are positive integers, and m = n; then am= 1 an
GREATEST COMMON FACTOR The greatest common factor of two or more monomials is the common factor with the greatest coefficient and the greatest degree in each variable.
GREATEST COMMON FACTOR Find the GCF of 25x4y and 50x2y5 GCF = 25x2y
5-3 Monomial Factors of Polynomials
Dividing a Polynomial by a Monomial • Divide each term of the polynomial by the monomial and add the results.
Dividing Polynomials by Monomials • 5m + 35 = m + 7 5 • 7x2 + 14x = x + 2 7x
Factoring a Polynomial To factor: • Find the GCF • Divide each term by the GCF • Write the product
Examples • 5x2 + 10x • 4x5 – 6x3 + 14x • 8a2bc2 – 12ab2c2
5-4 Multiplying Binomials Mentally When multiplying two binomials both terms of each binomial must be multiplied by the other two terms
Binomial • A polynomial that has two terms 2x + 3 4x – 3y 3xy – 14 613 + 39z
Trinomial • A polynomial that has three terms 2x2 – 3x + 1 14 + 32z – 3x mn – m2 + n2
Multiplying binomials • Using the F.O.I.L method helps you remember the steps when multiplying
F.O.I.L. Method • F – multiply First terms • O – multiply Outer terms • I – multiply Inner terms • L – multiply Last terms • Add all terms to get product
Example:(2a – b)(3a + 5b) • F – 2a · 3a • O – 2a · 5b • I – (-b) ▪ 3a • L - (-b) ▪ 5b • 6a2 + 10ab – 3ab – 5b2 • 6a2 + 7ab – 5b2
Example:(x + 6)(x +4) • F – x ▪ x • O – x ▪ 4 • I – 6 ▪ x • L – 6 ▪ 4 • x2 + 4x + 6x + 24 • x2 + 10x + 24
Section 5-5 Difference of Two Squares
Multiplying (x + 3) (x - 3) = ? (y - 2)(y + 2) = ? (s + 6)(s – 6) = ?
Factoring Pattern a2 – b2 =(a –b) (a + b)
FACTOR x2 - 49 = ? 16 – y2 = ? 81t2 – 25x6 = ?
Examples - Multiply (x + 3)2 = ? (y - 2)2 = ? (s + 6)2 = ?
Factoring Patterns (a + b)2 = a2 + 2ab + b2 (a - b)2 = a2 - 2ab + b2 • Also known as Perfect square trinomials
Examples – Factor • 4x2 + 20x + 25 • 64u2 + 72uv + 81v2 • 9m2 – 12m + 4 • 25y2 + 5y + 1
5-7 Factoring Pattern for x2 + bx + c, c positive
Example x2 + 8x + 15 Middle term is the sum of 3 and 5 Last term is the product of 3 and 5
Example y2 + 14y + 40 Middle term is the sum of 10 and 4 Last term is the product of 10 and 4
Example y2– 11y + 18 Middle term is the sum of -2 and -9 Last term is the product of -2and -9
Factor • m2 – 3m + 5 • k2 + 9k + 20 • y2 – 9y + 8
5-8 Factoring Pattern for x2 + bx + c, c negative
x2 - x - 20 Middle term is the sum of 4 and -5 Last term is the product of 4 and -5
Example y2 + 6y -40 Middle term is the sum of 10 and -4 Last term is the product of 10 and -4
Example y2– 7y - 18 Middle term is the sum of 2 and -9 Last term is the product of 2 and -9
Factor • x2 – 4kx – 12k2 • p2 – 32p – 33 • a2 + 3ab – 18b2
5-9 Factoring Pattern for ax2 + bx + c • List the factors of ax2 • List the factors of c • Test the possibilities to see which produces the correct middle term
Examples • 2x2 + 7x – 9 • 14x2 - 17x + 5 • 10 + 11x – 6x2 • 5a2 – ab – 22b2
5 -10 Factor by Grouping • Factor each polynomial by grouping terms that have a common factor • Then factor out the common factor and write the polynomial as a product of two factors
Examples • xy – xz – 3y + 3z • 3xy – 4 – 6x + 2y • xy + 3y + 2x + 6 • ab – 2b + ac – 2c • 9p2 – t2 – 4ts – 4s2
5 -11 Using Several Methods of Factoring • A polynomial is factored completely when it is expressed as the product of a monomial and one or more prime polynomials.
Guidelines for Factoring Completely • Factor out the greatest monomial factor first • Factor the remaining polynomial