+386 I have to find the rationnal roots for
12x^2 -6x -90
Now I know I have to use Gauss's r=v/u where v divides -90 and u divides 12...
would it be ok to divide the whole polinomial by 3 so it would narrow down the number of potential rationnal roots?
Would that eliminate only options that wouldn't end up being the right ones?
Thanks a lot!
+23251 To factor 12x2 - 6x - 90, it would be OK to start by factoring out 3:
---> 12x2 - 6x - 90 = 3(4x2 - 2x - 30)
This reduces the number of options without removing any possibly correct factors.
Also, if you look at 4x2 - 2x - 30 you may notice that each of the coefficients is an even number, meaning that you can now factor out a 2, making the problem simpler.
By factoring out both a 3 and a 2, you are factoring out a 6:
---> 12x2 - 6x - 90 = 6(2x2 - x - 15)
leaving you with far fewer possibilities.
