find the lim as x approaches positive and negative infinity
(3x^3 - x +1) / (x + 3)
can you explain the answer
Another way to do this to go ahead and divide: . As x goes to either + or - infinity, that last fraction goes to 0 so you only need to consider what happens to determines the limit.
If you know what a "horizontal asymptote" is, you should realize that knowing the limit tells you everything you need to know about the horizontal asymptotes.