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Factoring Out GCF
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Aug 18, 2015

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Page 1: 8 factoring out gcf

Factoring Out GCF

Page 2: 8 factoring out gcf

To factor means to rewrite a quantity as a product (in a nontrivial way).

Factoring Out GCF

Page 3: 8 factoring out gcf

To factor means to rewrite a quantity as a product (in a nontrivial way). A quantity x that can’t be written as product besides as 1*x is said to be prime.

Factoring Out GCF

Page 4: 8 factoring out gcf

To factor means to rewrite a quantity as a product (in a nontrivial way). A quantity x that can’t be written as product besides as 1*x is said to be prime. To factor completely means each factor in the product is prime.

Factoring Out GCF

Page 5: 8 factoring out gcf

Example A. Factor 12 completely.

To factor means to rewrite a quantity as a product (in a nontrivial way). A quantity x that can’t be written as product besides as 1*x is said to be prime. To factor completely means each factor in the product is prime.

Factoring Out GCF

Page 6: 8 factoring out gcf

Example A. Factor 12 completely.

12 = 3 * 4 = 3 * 2 * 2

To factor means to rewrite a quantity as a product (in a nontrivial way). A quantity x that can’t be written as product besides as 1*x is said to be prime. To factor completely means each factor in the product is prime.

Factoring Out GCF

Page 7: 8 factoring out gcf

Example A. Factor 12 completely.

12 = 3 * 4 = 3 * 2 * 2

not prime, incomplete

factored completely

To factor means to rewrite a quantity as a product (in a nontrivial way). A quantity x that can’t be written as product besides as 1*x is said to be prime. To factor completely means each factor in the product is prime.

Factoring Out GCF

Page 8: 8 factoring out gcf

Example A. Factor 12 completely.

12 = 3 * 4 = 3 * 2 * 2

not prime factored completely

To factor means to rewrite a quantity as a product (in a nontrivial way). A quantity x that can’t be written as product besides as 1*x is said to be prime. To factor completely means each factor in the product is prime.

Factoring Out GCF

A common factor of two or more quantities is a factor belongs to all the quantities.

Page 9: 8 factoring out gcf

Example A. Factor 12 completely.

12 = 3 * 4 = 3 * 2 * 2

not prime factored completely

To factor means to rewrite a quantity as a product (in a nontrivial way). A quantity x that can’t be written as product besides as 1*x is said to be prime. To factor completely means each factor in the product is prime.

Factoring Out GCF

Example B.

a. Sincer 6 = 2*3, 15 = 3*5,

A common factor of two or more quantities is a factor belongs to all the quantities.

Page 10: 8 factoring out gcf

Example A. Factor 12 completely.

12 = 3 * 4 = 3 * 2 * 2

not prime factored completely

To factor means to rewrite a quantity as a product (in a nontrivial way). A quantity x that can’t be written as product besides as 1*x is said to be prime. To factor completely means each factor in the product is prime.

Factoring Out GCF

Example B.

a. Sincer 6 = 2*3, 15 = 3*5, 3 is a common factor.

A common factor of two or more quantities is a factor belongs to all the quantities.

Page 11: 8 factoring out gcf

Example A. Factor 12 completely.

12 = 3 * 4 = 3 * 2 * 2

not prime factored completely

To factor means to rewrite a quantity as a product (in a nontrivial way). A quantity x that can’t be written as product besides as 1*x is said to be prime. To factor completely means each factor in the product is prime.

Factoring Out GCF

Example B.

a. Sincer 6 = 2*3, 15 = 3*5, 3 is a common factor.b. The common factor of 4ab, 6a are

A common factor of two or more quantities is a factor belongs to all the quantities.

Page 12: 8 factoring out gcf

Example A. Factor 12 completely.

12 = 3 * 4 = 3 * 2 * 2

not prime factored completely

To factor means to rewrite a quantity as a product (in a nontrivial way). A quantity x that can’t be written as product besides as 1*x is said to be prime. To factor completely means each factor in the product is prime.

Factoring Out GCF

Example B.

a. Sincer 6 = 2*3, 15 = 3*5, 3 is a common factor.b. The common factor of 4ab, 6a are 2,

A common factor of two or more quantities is a factor belongs to all the quantities.

Page 13: 8 factoring out gcf

Example A. Factor 12 completely.

12 = 3 * 4 = 3 * 2 * 2

not prime factored completely

To factor means to rewrite a quantity as a product (in a nontrivial way). A quantity x that can’t be written as product besides as 1*x is said to be prime. To factor completely means each factor in the product is prime.

Factoring Out GCF

Example B.

a. Sincer 6 = 2*3, 15 = 3*5, 3 is a common factor.b. The common factor of 4ab, 6a are 2, a,

A common factor of two or more quantities is a factor belongs to all the quantities.

Page 14: 8 factoring out gcf

Example A. Factor 12 completely.

12 = 3 * 4 = 3 * 2 * 2

not prime factored completely

To factor means to rewrite a quantity as a product (in a nontrivial way). A quantity x that can’t be written as product besides as 1*x is said to be prime. To factor completely means each factor in the product is prime.

Factoring Out GCF

Example B.

a. Sincer 6 = 2*3, 15 = 3*5, 3 is a common factor.b. The common factor of 4ab, 6a are 2, a, 2a.

A common factor of two or more quantities is a factor belongs to all the quantities.

Page 15: 8 factoring out gcf

Example A. Factor 12 completely.

12 = 3 * 4 = 3 * 2 * 2

not prime factored completely

To factor means to rewrite a quantity as a product (in a nontrivial way). A quantity x that can’t be written as product besides as 1*x is said to be prime. To factor completely means each factor in the product is prime.

Factoring Out GCF

Example B.

a. Sincer 6 = 2*3, 15 = 3*5, 3 is a common factor.b. The common factor of 4ab, 6a are 2, a, 2a.c. The common factors of 6xy2, 15x2y2 are

A common factor of two or more quantities is a factor belongs to all the quantities.

Page 16: 8 factoring out gcf

Example A. Factor 12 completely.

12 = 3 * 4 = 3 * 2 * 2

not prime factored completely

To factor means to rewrite a quantity as a product (in a nontrivial way). A quantity x that can’t be written as product besides as 1*x is said to be prime. To factor completely means each factor in the product is prime.

Factoring Out GCF

Example B.

a. Sincer 6 = 2*3, 15 = 3*5, 3 is a common factor.b. The common factor of 4ab, 6a are 2, a, 2a.c. The common factors of 6xy2, 15x2y2 are 3,

A common factor of two or more quantities is a factor belongs to all the quantities.

Page 17: 8 factoring out gcf

Example A. Factor 12 completely.

12 = 3 * 4 = 3 * 2 * 2

not prime factored completely

To factor means to rewrite a quantity as a product (in a nontrivial way). A quantity x that can’t be written as product besides as 1*x is said to be prime. To factor completely means each factor in the product is prime.

Factoring Out GCF

Example B.

a. Sincer 6 = 2*3, 15 = 3*5, 3 is a common factor.b. The common factor of 4ab, 6a are 2, a, 2a.c. The common factors of 6xy2, 15x2y2 are 3, x,

A common factor of two or more quantities is a factor belongs to all the quantities.

Page 18: 8 factoring out gcf

Example A. Factor 12 completely.

12 = 3 * 4 = 3 * 2 * 2

not prime factored completely

To factor means to rewrite a quantity as a product (in a nontrivial way). A quantity x that can’t be written as product besides as 1*x is said to be prime. To factor completely means each factor in the product is prime.

Factoring Out GCF

Example B.

a. Sincer 6 = 2*3, 15 = 3*5, 3 is a common factor.b. The common factor of 4ab, 6a are 2, a, 2a.c. The common factors of 6xy2, 15x2y2 are 3, x, y2,

A common factor of two or more quantities is a factor belongs to all the quantities.

Page 19: 8 factoring out gcf

Example A. Factor 12 completely.

12 = 3 * 4 = 3 * 2 * 2

not prime factored completely

To factor means to rewrite a quantity as a product (in a nontrivial way). A quantity x that can’t be written as product besides as 1*x is said to be prime. To factor completely means each factor in the product is prime.

Factoring Out GCF

Example B.

a. Sincer 6 = 2*3, 15 = 3*5, 3 is a common factor.b. The common factor of 4ab, 6a are 2, a, 2a.c. The common factors of 6xy2, 15x2y2 are 3, x, y2, xy2, ..

A common factor of two or more quantities is a factor belongs to all the quantities.

Page 20: 8 factoring out gcf

Example A. Factor 12 completely.

12 = 3 * 4 = 3 * 2 * 2

not prime factored completely

To factor means to rewrite a quantity as a product (in a nontrivial way). A quantity x that can’t be written as product besides as 1*x is said to be prime. To factor completely means each factor in the product is prime.

Factoring Out GCF

Example B.

a. Sincer 6 = 2*3, 15 = 3*5, 3 is a common factor.b. The common factor of 4ab, 6a are 2, a, 2a.c. The common factors of 6xy2, 15x2y2 are 3, x, y2, xy2, ..d. The common factor of a(x+y), b(x+y) is (x+y).

A common factor of two or more quantities is a factor belongs to all the quantities.

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The greatest common factor (GCF) is the common factor that has the largest coefficient and highest degree of each factor among all common factors.

Factoring Out GCF

Page 22: 8 factoring out gcf

The greatest common factor (GCF) is the common factor that has the largest coefficient and highest degree of each factor among all common factors.

Factoring Out GCF

Example C. Find the GCF of the given quantities.

a. GCF{24, 36}

Page 23: 8 factoring out gcf

The greatest common factor (GCF) is the common factor that has the largest coefficient and highest degree of each factor among all common factors.

Factoring Out GCF

Example C. Find the GCF of the given quantities.

a. GCF{24, 36} = 12.

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The greatest common factor (GCF) is the common factor that has the largest coefficient and highest degree of each factor among all common factors.

Factoring Out GCF

Example C. Find the GCF of the given quantities.

a. GCF{24, 36} = 12.b. GCF{4ab, 6a}

Page 25: 8 factoring out gcf

The greatest common factor (GCF) is the common factor that has the largest coefficient and highest degree of each factor among all common factors.

Factoring Out GCF

Example C. Find the GCF of the given quantities.

a. GCF{24, 36} = 12.b. GCF{4ab, 6a} = 2a.

Page 26: 8 factoring out gcf

The greatest common factor (GCF) is the common factor that has the largest coefficient and highest degree of each factor among all common factors.

Factoring Out GCF

Example C. Find the GCF of the given quantities.

a. GCF{24, 36} = 12.b. GCF{4ab, 6a} = 2a. c. GCF {6xy2, 15 x2y2}

Page 27: 8 factoring out gcf

The greatest common factor (GCF) is the common factor that has the largest coefficient and highest degree of each factor among all common factors.

Factoring Out GCF

Example C. Find the GCF of the given quantities.

a. GCF{24, 36} = 12.b. GCF{4ab, 6a} = 2a. c. GCF {6xy2, 15 x2y2} = 3xy2.

Page 28: 8 factoring out gcf

The greatest common factor (GCF) is the common factor that has the largest coefficient and highest degree of each factor among all common factors.

Factoring Out GCF

Example C. Find the GCF of the given quantities.

a. GCF{24, 36} = 12.b. GCF{4ab, 6a} = 2a. c. GCF {6xy2, 15 x2y2} = 3xy2.d. GCF{x3y5, x4y6, x5y4} =

Page 29: 8 factoring out gcf

The greatest common factor (GCF) is the common factor that has the largest coefficient and highest degree of each factor among all common factors.

Factoring Out GCF

Example C. Find the GCF of the given quantities.

a. GCF{24, 36} = 12.b. GCF{4ab, 6a} = 2a. c. GCF {6xy2, 15 x2y2} = 3xy2.d. GCF{x3y5, x4y6, x5y4} = x3y4.

Page 30: 8 factoring out gcf

The greatest common factor (GCF) is the common factor that has the largest coefficient and highest degree of each factor among all common factors.

Factoring Out GCF

Example C. Find the GCF of the given quantities.

a. GCF{24, 36} = 12.b. GCF{4ab, 6a} = 2a. c. GCF {6xy2, 15 x2y2} = 3xy2.d. GCF{x3y5, x4y6, x5y4} = x3y4.

The Extraction LawDistributive law interpreted backward gives the Extraction Law, that is, common factors may be extracted from sums or differences.

Page 31: 8 factoring out gcf

The greatest common factor (GCF) is the common factor that has the largest coefficient and highest degree of each factor among all common factors.

Factoring Out GCF

Example C. Find the GCF of the given quantities.

a. GCF{24, 36} = 12.b. GCF{4ab, 6a} = 2a. c. GCF {6xy2, 15 x2y2} = 3xy2.d. GCF{x3y5, x4y6, x5y4} = x3y4.

The Extraction LawDistributive law interpreted backward gives the Extraction Law, that is, common factors may be extracted from sums or differences.

AB ± AC A(B±C)

Page 32: 8 factoring out gcf

The greatest common factor (GCF) is the common factor that has the largest coefficient and highest degree of each factor among all common factors.

Factoring Out GCF

Example C. Find the GCF of the given quantities.

a. GCF{24, 36} = 12.b. GCF{4ab, 6a} = 2a. c. GCF {6xy2, 15 x2y2} = 3xy2.d. GCF{x3y5, x4y6, x5y4} = x3y4.

The Extraction LawDistributive law interpreted backward gives the Extraction Law, that is, common factors may be extracted from sums or differences.

AB ± AC A(B±C)

This procedure is also called “factoring out a common factor”. To factor, the first step always is to factor out the GCF.

Page 33: 8 factoring out gcf

Factoring Out GCFExample D. Factor out the GCF.a. xy – 4y

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(the GCF is y)

Factoring Out GCFExample D. Factor out the GCF.a. xy – 4y

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(the GCF is y)

Factoring Out GCFExample D. Factor out the GCF.a. xy – 4y = y(x – 4)

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(the GCF is y)

Factoring Out GCFExample D. Factor out the GCF.a. xy – 4y = y(x – 4)

b. 4ab + 6a

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(the GCF is y)

(the GCF is 2a)

Factoring Out GCFExample D. Factor out the GCF.a. xy – 4y = y(x – 4)

b. 4ab + 6a

Page 38: 8 factoring out gcf

(the GCF is y)

(the GCF is 2a)

Factoring Out GCFExample D. Factor out the GCF.a. xy – 4y = y(x – 4)

b. 4ab + 6a = 2a(2b) + 2a(3)

Page 39: 8 factoring out gcf

(the GCF is y)

(the GCF is 2a)

Factoring Out GCFExample D. Factor out the GCF.a. xy – 4y = y(x – 4)

b. 4ab + 6a = 2a(2b) + 2a(3) = 2a(2b + 3)

Page 40: 8 factoring out gcf

(the GCF is y)

(the GCF is 2a)

Factoring Out GCFExample D. Factor out the GCF.a. xy – 4y = y(x – 4)

b. 4ab + 6a = 2a(2b) + 2a(3) = 2a(2b + 3)

c. 12x2y3 + 6x2y2

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(the GCF is y)

(the GCF is 2a)

(the GCF is 6x2y2)

Factoring Out GCFExample D. Factor out the GCF.a. xy – 4y = y(x – 4)

b. 4ab + 6a = 2a(2b) + 2a(3) = 2a(2b + 3)

c. 12x2y3 + 6x2y2

Page 42: 8 factoring out gcf

(the GCF is y)

(the GCF is 2a)

(the GCF is 6x2y2)

Factoring Out GCFExample D. Factor out the GCF.a. xy – 4y = y(x – 4)

b. 4ab + 6a = 2a(2b) + 2a(3) = 2a(2b + 3)

c. 12x2y3 + 6x2y2 = 6x2y2(2y) + 6x2y2(1)

Page 43: 8 factoring out gcf

(the GCF is y)

(the GCF is 2a)

(the GCF is 6x2y2)

Factoring Out GCFExample D. Factor out the GCF.a. xy – 4y = y(x – 4)

b. 4ab + 6a = 2a(2b) + 2a(3) = 2a(2b + 3)

c. 12x2y3 + 6x2y2 = 6x2y2(2y) + 6x2y2(1) = 6x2y2(2y + 1)

Page 44: 8 factoring out gcf

Factoring Out GCF

We may pull out common factors that are ( )'s.

(the GCF is y)

(the GCF is 2a)

(the GCF is 6x2y2)

Example D. Factor out the GCF.a. xy – 4y = y(x – 4)

b. 4ab + 6a = 2a(2b) + 2a(3) = 2a(2b + 3)

c. 12x2y3 + 6x2y2 = 6x2y2(2y) + 6x2y2(1) = 6x2y2(2y + 1)

Page 45: 8 factoring out gcf

Factoring Out GCF

We may pull out common factors that are ( )'s.

Example E. Factor

a. a(x + y) – 4(x + y)

(the GCF is y)

(the GCF is 2a)

(the GCF is 6x2y2)

Example D. Factor out the GCF.a. xy – 4y = y(x – 4)

b. 4ab + 6a = 2a(2b) + 2a(3) = 2a(2b + 3)

c. 12x2y3 + 6x2y2 = 6x2y2(2y) + 6x2y2(1) = 6x2y2(2y + 1)

Page 46: 8 factoring out gcf

Factoring Out GCF

We may pull out common factors that are ( )'s.

Example E. Factor

a. a(x + y) – 4(x + y) Pull out the common factor (x + y)

(the GCF is y)

(the GCF is 2a)

(the GCF is 6x2y2)

Example D. Factor out the GCF.a. xy – 4y = y(x – 4)

b. 4ab + 6a = 2a(2b) + 2a(3) = 2a(2b + 3)

c. 12x2y3 + 6x2y2 = 6x2y2(2y) + 6x2y2(1) = 6x2y2(2y + 1)

Page 47: 8 factoring out gcf

Factoring Out GCF

We may pull out common factors that are ( )'s.

Example E. Factor

a. a(x + y) – 4(x + y) Pull out the common factor (x + y) a(x + y) – 4(x + y) = (x + y)(a – 4)

(the GCF is y)

(the GCF is 2a)

(the GCF is 6x2y2)

Example D. Factor out the GCF.a. xy – 4y = y(x – 4)

b. 4ab + 6a = 2a(2b) + 2a(3) = 2a(2b + 3)

c. 12x2y3 + 6x2y2 = 6x2y2(2y) + 6x2y2(1) = 6x2y2(2y + 1)

Page 48: 8 factoring out gcf

Factoring Out GCF

We may pull out common factors that are ( )'s.

Example E. Factor

a. a(x + y) – 4(x + y) Pull out the common factor (x + y) a(x + y) – 4(x + y) = (x + y)(a – 4)

b. Factor (2x – 3)3x – 2(2x – 3)

(the GCF is y)

(the GCF is 2a)

(the GCF is 6x2y2)

Example D. Factor out the GCF.a. xy – 4y = y(x – 4)

b. 4ab + 6a = 2a(2b) + 2a(3) = 2a(2b + 3)

c. 12x2y3 + 6x2y2 = 6x2y2(2y) + 6x2y2(1) = 6x2y2(2y + 1)

Page 49: 8 factoring out gcf

Factoring Out GCF

We may pull out common factors that are ( )'s.

Example E. Factor

a. a(x + y) – 4(x + y) Pull out the common factor (x + y) a(x + y) – 4(x + y) = (x + y)(a – 4)

b. Factor (2x – 3)3x – 2(2x – 3) Pull out the common factor (2x – 3),

(the GCF is y)

(the GCF is 2a)

(the GCF is 6x2y2)

Example D. Factor out the GCF.a. xy – 4y = y(x – 4)

b. 4ab + 6a = 2a(2b) + 2a(3) = 2a(2b + 3)

c. 12x2y3 + 6x2y2 = 6x2y2(2y) + 6x2y2(1) = 6x2y2(2y + 1)

Page 50: 8 factoring out gcf

Factoring Out GCF

We may pull out common factors that are ( )'s.

Example E. Factor

a. a(x + y) – 4(x + y) Pull out the common factor (x + y) a(x + y) – 4(x + y) = (x + y)(a – 4)

b. Factor (2x – 3)3x – 2(2x – 3) Pull out the common factor (2x – 3), (2x – 3)3x – 2(2x – 3) = (2x – 3)(3x – 2)

(the GCF is y)

(the GCF is 2a)

(the GCF is 6x2y2)

Example D. Factor out the GCF.a. xy – 4y = y(x – 4)

b. 4ab + 6a = 2a(2b) + 2a(3) = 2a(2b + 3)

c. 12x2y3 + 6x2y2 = 6x2y2(2y) + 6x2y2(1) = 6x2y2(2y + 1)

Page 51: 8 factoring out gcf

Factoring Out GCFWe sometimes pull out a negative sign from an expression.

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Factoring Out GCF

Example F. Pull out the negative sign from –2x + 5.

We sometimes pull out a negative sign from an expression.

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Factoring Out GCF

Example F. Pull out the negative sign from –2x + 5.

–2x + 5 = –(2x – 5)

We sometimes pull out a negative sign from an expression.

Page 54: 8 factoring out gcf

Factoring Out GCF

Example F. Pull out the negative sign from –2x + 5.

–2x + 5 = –(2x – 5)

Sometime we have to use factor twice.

We sometimes pull out a negative sign from an expression.

Page 55: 8 factoring out gcf

Example G. Factor by pulling out twice.

a. y(2x – 5) – 2x + 5

Factoring Out GCF

Example F. Pull out the negative sign from –2x + 5.

–2x + 5 = –(2x – 5)

Sometime we have to use factor twice.

We sometimes pull out a negative sign from an expression.

Page 56: 8 factoring out gcf

Example G. Factor by pulling out twice.

a. y(2x – 5) – 2x + 5 = y(2x – 5) – (2x – 5)

Factoring Out GCF

Example F. Pull out the negative sign from –2x + 5.

–2x + 5 = –(2x – 5)

Sometime we have to use factor twice.

We sometimes pull out a negative sign from an expression.

Page 57: 8 factoring out gcf

Example G. Factor by pulling out twice.

a. y(2x – 5) – 2x + 5 = y(2x – 5) – (2x – 5) = (2x – 5)(y – 1)

Factoring Out GCF

Example F. Pull out the negative sign from –2x + 5.

–2x + 5 = –(2x – 5)

Sometime we have to use factor twice.

We sometimes pull out a negative sign from an expression.

Page 58: 8 factoring out gcf

Example G. Factor by pulling out twice.

a. y(2x – 5) – 2x + 5 = y(2x – 5) – (2x – 5) = (2x – 5)(y – 1)

b. 3x – 3y + ax – ay

Factoring Out GCF

Example F. Pull out the negative sign from –2x + 5.

–2x + 5 = –(2x – 5)

Sometime we have to use factor twice.

We sometimes pull out a negative sign from an expression.

Page 59: 8 factoring out gcf

We sometimes pull out a negative sign from an expression.

Example G. Factor by pulling out twice.

a. y(2x – 5) – 2x + 5 = y(2x – 5) – (2x – 5) = (2x – 5)(y – 1)

b. 3x – 3y + ax – ay Group them into two groups. = (3x – 3y) + (ax – ay)

Factoring Out GCF

Example F. Pull out the negative sign from –2x + 5.

–2x + 5 = –(2x – 5)

Sometime we have to use factor twice.

Page 60: 8 factoring out gcf

Example G. Factor by pulling out twice.

a. y(2x – 5) – 2x + 5 = y(2x – 5) – (2x – 5) = (2x – 5)(y – 1)

b. 3x – 3y + ax – ay Group them into two groups. = (3x – 3y) + (ax – ay) Factor out the GCF of each group. = 3(x – y) + a(x – y)

Factoring Out GCF

Example F. Pull out the negative sign from –2x + 5.

–2x + 5 = –(2x – 5)

Sometime we have to use factor twice.

We sometimes pull out a negative sign from an expression.

Page 61: 8 factoring out gcf

Factoring Out GCF

Example F. Pull out the negative sign from –2x + 5.

–2x + 5 = –(2x – 5)

Sometime we have to use factor twice.

Example G. Factor by pulling out twice.

a. y(2x – 5) – 2x + 5 = y(2x – 5) – (2x – 5) = (2x – 5)(y – 1)

b. 3x – 3y + ax – ay Group them into two groups. = (3x – 3y) + (ax – ay) Factor out the GCF of each group. = 3(x – y) + a(x – y) Pull the factor (x – y) again. = (3 + a)(x – y)

We sometimes pull out a negative sign from an expression.