1. Factoring Review 25 January 2011

2. Factoring The process of rewriting an equation or expression as the product of its factors Example: x 2 + 3x + 2 = (x + 2)(x + 1) Most common form is the quadratic form: ax 2 + bx + c, a ≠ 0

3. Factoring (when a = 1) ax 2 + bx + c = (x + ___ ) (x + ___ ) multiply to equal c and add up to equal b You can always check your answer by FOIL-ing!

4. Finding Factors of C 1. Identify the value of c 2. On your calculator, go to the y= screen 3. Type C/X into y1 4. Go to the table 5. Any whole numbers (positive, non- decimal numbers) in the y1 column are factors of c

5. Example

6. Example #1

7. Example #2

8. Example #3

9. Your Turn: Complete problems 1 – 4 on the “Factoring Practice” handout Check your answer by FOIL-ing!

10. Difference of Squares When we use it: Usually in the form ax 2 – c Both a and c are perfect squares (the square root of each number is a whole number)

11. Example #1

12. Example #2

13. Your Turn: Complete problems 5 – 10 on the “Factoring Practice” handout Remember to check your answer by FOIL-ing!

14. Factoring (when a ≠ 1): The Welsh Method Pt. I 1. Multiply c and a 2. Rewrite the expression with the new value for c 3. Write (ax + )(ax + ) 4. Finish “factoring” the new expression 5. Reduce each set of parentheses by any common factors

15. Example #1

16. Example #2

17. Example #3

18. Your Turn: Complete problems 11 – 20 on the “Factoring Practice” handout Don’t forget to check by FOIL-ing!

19. GCF (Greatest Common Factor) When we use it: when the all the terms share 1 or more factors Factoring out GCFs save us time!!!

20. GCF (Greatest Common Factor) Steps: 1. Identify any common factor(s) (including the GCF) 2. Factor out the common factor(s) 3. Factor the remaining expression if possible

21. Example #1

22. Example #2

23. Example #3

24. Your Turn: Complete problems 1 – 10 on “Functions Practice Pt. II” handout

25. GCFs and The Welsh Method Make sure you factor out any GCFs or the Welsh Method doesn’t work!!!

26. Your Turn: Complete problems 11 – 22 on the “Factoring Practice Part II” handout