1. Factoring Review
25 January 2011

2. Factoring
The process of rewriting an equation or expression as the product of its factors
Example: x2 + 3x + 2 = (x + 2)(x + 1)
Most common form is the quadratic form: ax2 + bx + c, a ≠ 0

3. Factoring (when a = 1) ax2 + 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 Identify the value of c
On your calculator, go to the y= screen
Type C/X into y1
Go to the table
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 ax2 – 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
Multiply c and a
Rewrite the expression with the new value for c
Write (ax + )(ax + )
Finish “factoring” the new expression
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!