Let us use the Rational Zeros Theorem to find all possible solutions of this function.

Factors of leading coefficient (4): 1, 2, 4

Factors of lone constant (3): 1, 3

Possible solutions:

Using Descartes' Rule of Signs, note there is one changes in sign when going through the equation. (+ to -, - to -... + to - is only change of sign). This means there is one positive x-intercept for this function, and it is one of the six given through the Rational Zeros Theorem.