The worse version of Rational Root Theorem. Only works if you have a leading coefficient that is 1.
Utilization
Find all factors of the leading coefficient * 6
So, for example, with the function: f(x) = x^3 - 4x^2 + x + 6. we want to find the factors of 1 * 6.
The factors are: +-1, +-2, +-3, +-4.
Use the Factor Theorem with every one of these factors and check if they are zero to determine the factors.
Testing the factors
f(1) = 4 f(-1) = 0!! Its factor! f(2) = 0!! f(-2) = -20 f(3) = 0!! f(-3) = -60 f(6) = 84 f(-6) = -360