## careless850 3 years ago Simplify.. again!

1. karatechopper

what to simplify?

2. careless850

$\frac {x^{2}-12x+20}{x-10}$

3. phi

you have to factor the top.

4. careless850

So, it'd be, x - 3x + 5?

5. phi

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)

6. careless850

Alright.. I didn't know about that part.

7. phi

once you have it factored up top, we can cancel the (x-10) from top and bottom

8. careless850

but wait..

9. careless850

What if I don't know the factors with numbers?

10. phi

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

11. careless850

but I'm Simplifying Algebraic Ratios

12. phi

That means they think you know algebra, including factoring quadratics

13. careless850

Would the answer be x-2?

14. phi

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!

15. careless850

I see. And I lied about the factoring thing, I can factor numbers that are even or divisible by 5

16. phi

If the video helps, notice that Khan has LOTS of videos on pretty much any topic you might have a question on.