5.3 Factoring Quadratic Expressions Cont'd

Scribe:  Madeline Babuka Black

Factoring ax^2+bx+c when a≠1:

HIGHLIGHTS OF BOX METHOD:
factor

6x	9x
2x	3

      2x            3
(right side is 3x on top and 1 on bottom)

1: two numbers that multiply to give you 18 and add to give you 11
2: use sign of whatever lead box would be

Factoring the difference of two squares: a^2- b^2 = (a+b)(a-b)
 
EX 9: x^2- 4 ---> (x)^2- (2)^2 ---> (x+2)(x-2)

EX 10: x^4- 121 ---> (x^2)^2- (11)^2 ---> (x^2-11)(x^2-11)

EX 11: 16x^4- 81 ---> (4x^2)^2- (9)^2 ---> (4x^2+9)(4x^2-9) ---> (4x^2+9) ((2x)^2+3^2) ---> (4x^2+9)(2x+3)(2x-3)

*you can sometimes use factoring to solve and equation and find all the zeros