# 5.3 - Mr. K's Virtual World of Math

```2.3 Factor and Solve
Polynomial Expressions
Pg.
76
Factoring:
• When Factoring expressions, there is an order
– GCF
3a 2  6a  3a(a  2)
• Greatest Common Factor
• This is for any polynomial
– Difference of Perfect Squares
• Each term must be a perfect square
• Coefficients must be perfect squares and even
exponents on the variables
• This is for only BINOMIALS
– Reverse Foil
• Finding the factors of the “C” term that when added
together make the “B” term with the correct sign
Remember to Completely Factor
GCF
(Greatest Common Factor)
3a  6a 
2
x y x y 
2 3
3 2
3 x  12 x  12 x 
3
2
Difference of Perfect Squares
• Must be a Binomial
• Must have subtraction between the terms
x 9
2
4 x  36
2
25 x 2  49 y 4
Reverse Foil Factoring x2 + bx + c
• To factor an expression of the form
ax2 +bx + c where a =1
Look for integers “r and s”
such that (r) (s) = c and r + s = b.
Then use “r &amp; s” in the factors of the expression.
x 2  bx  c  ( x  r )( x  s)
Example:
x  5x  6 
2
x 2  9 x  20 
x 2 7 x  30 
x 2  10 x  11 
Homework
Factoring Review
Worksheet #1
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