Simplifying rational expressions example 2 | Rational expressions | Algebra II | Khan Academy 

The best thing about these videos is you can pause the lesson to think about it, and even replay it if you missed something. Awesome stuff.

It's pretty easy to factorise in stuff like this by just putting (2x )(x ) on your page and the answer comes apparent to you quite quickly, but I guess splitting the middle term becomes useful when you have a coefficient of x^2 with a lot of factors (not just 2 and 1)

This is great for me since right now in taking a break from college, so this is a quick refresh... Lol

Where is the "last" video that proves that method? I tried to prove it (for this example)and came up with: A*B = 20 and 2B + A = 13. B=20/A. 2(20/A) + A = 13. (40 + A^2)/A = 13 or 40 + A^2 = 13A or A^2 -13A + 40 = 0 and hence why your "13x = Ax +Bx, A*B = 2*20" Method works.

just so you know, 20 and 3 does in fact multiply to 60 whilst equalling 17.

@MasterThief1324 It's not in "domain of a rational expression 1"