| |
|
| KU Interactive Mathematics |
|
|
| Help Files |
Rational Expressions (2)
Question: What’s the best way to do problems such as this?
|
Yours
Truly answers: There are three key steps. Factor every numerator & denominator, perform cancellation, and simplify.
| Step 1. |
Factorization |
| |
 |
| |
|
| |
It is the red part that makes this problem tricky. We use the identity a2 – b2 = (a + b)(a – b) with a = 2x and b = 3. This is a very useful formula, and we should memorize it. |
| |
|
| Step 2. |
Cancellation |
| |
|
| |
|
| Step 3. |
Simplify |
| |
What is left after the cancellation is the answer. |
| |
|
| |
|
|
|
| |
| Help Files |
|
| KU Interactive Mathematics |
|
Disclaimer • Updated
September 4, 2008
|
|
