Question 49182
a = f[1] and b = f[27]
factors: a = 1 and b = 1,3,9,27
+- b/a = +- 1,3,9,27
It is no a factor due to Descarte's Rule of Signs.
{{{graph(600,600,-10,10,-10,10,x^4+12x^3+6x+27)}}}