How do I shorten this? How do I have to think?
$$ x^2 + x – 2$$
The answer is
$$(x+2)(x-1)$$
I don't know how to get to the answer systematically. Could someone explain?
Does anyone have a link to a site that teaches basic stuff like this? My book does not explain anything and I have no teacher; this is self-studies.
Please help me out; thanks!
Best Answer
You might appreciate the series of Khan Academy lectures (+ practice problems, etc).
Each lesson is given via a short 12 minute video, which you can replay if needed: the link I'm including below should take you to "Algebra" lessons; but you might also want to look at "Developmental math I and II".
This is a great way to learn via video demonstrations, practice, repetition, etc., and if you stumble, say, with negative exponents, e.g., you can go directly to a lesson addressing the issue at hand. I believe there is diagnostic testing available (this is all free, no fees for watching videos, doing practice sets, tests, etc.), and such testing can really be helpful in learning where you need to direct your energies to move to the next level.
Edit: I've also come across this site, devoted to tutoring/demonstrating how to factor polynomials: it's developmental in approach, in that it starts slowly, with very common patterns used when factoring, and progresses in difficulty, building on what you've already learned, so best to approach the tutorial in the order given.