1. Lesson 6.1 Factoring by Greatest Common Factor
Objective:
To factor monomials and polynomials by greatest common factor

2. Vocabulary
Factors that are shared by two or more whole numbers are called common factors. The greatest of these common factors is called the greatest common factor, or GCF.
Factors of 12: 1, 2, 3, 4, 6, 12
Factors of 32: 1, 2, 4, 8, 16, 32

3. Example of finding GCF Find the GCF of each pair of numbers.
100 and 60

4. Example of finding GCF Find the GCF of each pair of monomials.
15x3 and 9x2

5. Example of finding GCF Find the GCF of each pair of monomials.
8x2 and 7y3

6. Example of finding GCF Helpful Hint
If two terms contain the same variable raised to different powers, the GCF will contain that variable raised to the lower power.
Helpful Hint
Find the GCF of each pair of monomials.
18g2 and 27g3

7. Example of finding GCF Find the GCF of each pair of monomials.
16a6 and 9b
8x and 7v2
27x2 and 45x3y2

8. Vocabulary Recall the Distributive Property: ab + ac =a(b + c)
The Distributive Property allows you to “factor” out the GCF of the terms in a polynomial to write a factored form of the polynomial.

9. Vocabulary
A polynomial is in its factored form when it is written as a product of monomials and polynomials that cannot be factored further.
The polynomial 2(3x – 4x) is not fully factored because the terms in the parentheses have a common factor of x.

10. Example of factoring by GCF
Factor each polynomial. Check your answer.
2x2 – 4
8x3 – 4x2 – 16x

11. Example of factoring by GCF
Factor each polynomial. Check your answer.
–14x – 12x2
5b + 9b3
3x3 + 2x2 – 10

12. Example of factoring by GCF
Factor each polynomial. Check your answer.
–18y3 – 7y2
8x4 + 4x3 – 2x2

13. Vocabulary
Sometimes the GCF of terms is a binomial. This GCF is called a common binomial factor.
You factor out a common binomial factor the same way you factor out a monomial factor.

14. Example of factoring by GCF
Factor each expression.
5(x + 2) + 3x(x + 2)
–2b(b2 + 1)+ (b2 + 1)
4z(z2 – 7) + 9(2z3 + 1)

15. Example of factoring by GCF
Factor each expression.
a. 4s(s + 6) – 5(s + 6)
b. 7x(2x + 3) + (2x + 3)

16. Example of factoring by GCF
Factor each expression.
c. 3x(y + 4) – 2y(x + 4)
d. 5x(5x – 2) – 2(5x – 2)

17. Example of factoring by GCF
Factor each polynomial by grouping. Check your answer.
6h4 – 4h3 + 12h – 8

18. Example of factoring by GCF
Factor each polynomial by grouping. Check your answer.
5y4 – 15y3 + y2 – 3y

19. Example of factoring by GCF
Factor each polynomial by grouping. Check your answer.
6b3 + 8b2 + 9b + 12
4r3 + 24r + r2 + 6

20. Example of factoring by GCF
Factor each polynomial by grouping. Check your answer.
2x3 – 12x – 3x.
15x2 – 10x3 + 8x – 12