1. The problem statement, all variables and given/known data Determine whether y(x)=x^3-7x^2+14x-4 is irreducible in Q[x] with only pen and paper. 3. The attempt at a solution The factor theorem would be good to use as if it isn't irreducible there must be a linear factor (x-a) with a in Q. I have worked out that at leat one zero does exist because for x<0, y(x)<0 & x>0, y(x)>0. But is this x value in Q or R?