Thread: proving roots irrational

My class was given an assignment of proving the roots of 3, 6, and 12 as irrational. I have solved 3 and 6, and tried using what I did there for 12, but it is not working out. Someone help me out please?
Here is the prob:
If n^2=12, then n is not rational.

Hi,

If you know that is an irrational number then you can use this :

wow... i have no idea why i kept overlooking that... i would always get to p^2=3q^2 (sorry, i am still tryin to learn how to much the computer math stuff) and i was so tryin to use the common factor that i didnt even notice what i was arriving at, thanks so much