This is highly urgent.

3x^5 - 19x^4 + 9x^3 + 71x^2 + 84x + 20 = 0.

We are looking for real solutions..

I believe there is only one - though, I have no idea how to find it. Horner's Method does not seem to be of use, neither do I seem to be able to rearrange anything in a beneficial way.