Find the roots of the polynomial x^3-2x^2-12x+9=0

x=3, (5+sqr(13))/2, (5-sqr(13))/2

Step-by-step explanation:

Factor x^3-2x^2-12x+9=0 and you get (x-3)(x^2-5x+3)=0

Set x-3=0 and you get 3 and if you set the second part equal to 0 then you'll realize that it's not factorable and you'll have to use the quadratic equation

Once you plug everything in then you'll get (5+sqr(13))/2, and (5-sqr(13))/2