section 12.2-12.4 - simplifying opposites

Review
3+4=7 (x+4) / (4+x) = 1
4+3=7

*5-2 = 3
*2-5 = -3

*3 / -3 = -1
*y-3 / 3-y = -1

* When canceling opposites, you have to include a "-1" after you cancel *

EX: simplify

3x^2 – 27 / 3x - x^2
= 3(x^2 – 9) / x(3 – x)
= (-1)3 (x + 3) (x – 3) / x(3 – x)
final answer: -3(x + 3) / x

EX:

[9 – 4x^2 / x^2 – 16] [x^2 + 6x + 8 / 4x – 6]
[(3 + 2x) / (x – 4)] [(x + 2) / 2]
final answer: [-(3 + 2x) (x + 2)] / [2(x – 4)]