Here's the question you clicked on:
careless850
Simplify.. again!
what to simplify?
\[\frac {x^{2}-12x+20}{x-10}\]
you have to factor the top.
So, it'd be, x - 3x + 5?
list the factors of the 3rd number 20 1,20 2,10 4,5 do any add up to 12 if so, that is the pair to use. the sign of the 2nd number (-12) tells you to make the factors negative I would use (x-2)(x-10)
Alright.. I didn't know about that part.
once you have it factored up top, we can cancel the (x-10) from top and bottom
What if I don't know the factors with numbers?
I think that means you have to practice.... Here is a video, when you have time http://www.khanacademy.org/math/algebra/polynomials/v/factoring-quadratic-expressions
but I'm Simplifying Algebraic Ratios
That means they think you know algebra, including factoring quadratics
Would the answer be x-2?
yes. you can test the answer pick a simple number like x=0. If your answer is correct (x-2) with x=0 is 0-2= -2 replace x=0 into the original problem: and you get 20/-10= -2 It matches!
I see. And I lied about the factoring thing, I can factor numbers that are even or divisible by 5
If the video helps, notice that Khan has LOTS of videos on pretty much any topic you might have a question on.