# Thread: Factoring

1. ## Factoring

Ok it's 3a squared-2a-21

2. Originally Posted by Itachi888Uchiha
Ok it's 3a squared-2a-21
$\displaystyle 3a^2 - 2a - 21 = 3a^2 + 7a - 9a - 21 = \, .....$

3. Originally Posted by mr fantastic
$\displaystyle 3a^2 - 2a - 21 = 3a^2 + 7a - 9a - 21 = \, .....$
Um, no parenthesis?

4. $\displaystyle 3a^2 - 2a - 21$

=$\displaystyle 3a^2 - 9a + 7a - 21$

=$\displaystyle 3a(a-3) +7(a-3)$

=$\displaystyle (3a + 7)(a - 3)$

5. Originally Posted by Itachi888Uchiha
Um, no parenthesis?
The implication of $\displaystyle = \, .....$ is that you continue working from where I left off.

The intent is to give you a push in the right direction without spoon feeding the entire solution to you.

6. Originally Posted by mr fantastic
The implication of $\displaystyle = \, .....$ is that you continue working from where I left off.

The intent is to give you a push in the right direction without spoon feeding the entire solution to you.
I didn't know what to do at all, and I didn't want to make up a problem because I wouldn't have been sure it worked. Now that, the other dude posted, I remember. It's been a long summer........

7. well id teach you but my answers tend to be wrong

but i think this guy explains it pretty good

[YOUTUBE]http://www.youtube.com/watch?v=2Q8lG1WaqJY[/YOUTUBE]