According to the Rational Root Theorem, if a polynomial equation has a rational root , then is a factor of the constant term and is a factor of the leading coefficient.
For the equation , the leading coefficient is 4 and the constant term is 6.
The factors of 4 are .
The factors of 6 are .
So the possible rational roots are .
Let's start testing these possible roots. Try .
Substituting into the equation: