This polynomial equation below, I solved using TI-82 and I only got one root:
so got the first root as 250. How do I find the other ones, or use this root to find out other ones?
Hawk, your link has the $x^0$ coefficient as 3 billion, not 3 million. Also, the root was only approximately 251. It seems nitpicky, but in some cases a small error in the root in your denominator can produce large errors in the subsequent roots.