http://en.wikipedia.org/wiki/L'H%C3%B4pital's_rule
Use L'Hopital's Rule
This is not exactly the question you wrote, but I think it is what you intended.
If I got the intention wrong then I am sorry.
lim [x 2 + x 3 - x] / [x 4 - x 2 +1]
x--> infinity
= lim [2x + 3x 2 - 1] / [4x 3 - 2x]
x--> infinity
= lim [2 + 6x ] / [12x 2 - 2 ]
x--> infinity
= lim 6/(24x)
x--> infinity
=0
+118652 
