1. Special Case Multiplication
CCM2 11-4

2. Difference of Squares Theorem
Statement
Consider two binomials that are the same except that the constants have opposite signs. i.e. …
Using FOIL we find…
Combining like terms …
Example
(a + b) (a – b)
a2 – ab + ab – b2
a2 – b2
The inside and outside terms always cancel out, giving the theorem:
(a + b) (a – b) = a2 – b2

3. You Try: Multiply the following:
(x + 3)(x – 3)
(2x + 1)(2x – 1)
(3x + 7)(3x – 7)
x2 - 9
4x2 - 1
9x2 - 49

4. Perfect Squares Theorem
Statement
Consider a binomial squared
Square means to multiply two factors
Using FOIL we find…
Combining like terms …
Example
(a + b)2
(a + b) (a + b)
a2 + ab + ab + b2
a2 + 2ab + b2
The inside and outside terms always are the same, giving the theorem:
(a + b)2= a2 + 2ab + b2

5. You Try: Multiply the following:
(x + 3)2
(2x – 1)2
(3x + 4)2
x2 + 6x + 9
4x2 + 4x + 1
9x2 + 24x + 16

6. Summary
Difference of Squares
Perfect Squares
Thank You