Post on 25-Feb-2016
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Factoring Review
25 January 2011
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
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!
Finding Factors of C1. Identify the value of c2. On your calculator, go to the y=
screen3. Type C/X into y14. Go to the table5. Any whole numbers (positive,
non-decimal numbers) in the y1 column are factors of c
Example
Example #1
24x11x2
Example #2
35x2x2
Example #3
12x7x2
Your Turn: Complete problems 1 – 4 on the
“Factoring Practice” handout Check your answer by FOIL-ing!
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)
)cxa)(cxa(
cax2
Example #1
81h2
Example #2
144j49 2
Your Turn: Complete problems 5 – 10 on the
“Factoring Practice” handout Remember to check your answer
by FOIL-ing!
Factoring (when a ≠ 1):The Welsh Method Pt. I
1. Multiply c and a2. Rewrite the expression with the new
value for c3. Write (ax + )(ax + )4. Finish “factoring” the new expression5. Reduce each set of parentheses by
any common factors
Example #14y13y3 2
Example #22x5x3 2
Example #32g5g7 2
Your Turn: Complete problems 11 – 20 on the
“Factoring Practice” handout Don’t forget to check by FOIL-ing!
GCF (Greatest Common Factor) When we use it: when the all the
terms share 1 or more factors Factoring out GCFs save us
time!!!
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
Example #1x3x2x 23
Example #264x32x4 2
Example #3234 y21y24y3
Your Turn: Complete problems 1 – 10 on
“Functions Practice Pt. II” handout
GCFs and The Welsh Method
20x14x2 2 Make sure you factor out any
GCFs or the Welsh Method
doesn’t work!!!
Your Turn: Complete problems 11 – 22 on the
“Factoring Practice Part II” handout