Hi - I am stuck on a question that requires me to find the 2nd point of intersection between a power function (x^3) and the tangent of the function at a given point (1/2, 1/8), which I determined to be y=3/4x - 1/4

I have combined the two equations and created a 3rd order trinomial 0=x^3 -3/4x +1/4. My problem is that I forget how to factor a trinomial with an odd power. Any help would be appreciated.

Thanks in advance.