As \( x \rightarrow \infty, f(x) \rightarrow \infty \) and as \( x \rightarrow -\infty, f(x) \rightarrow -\infty \).
Thus, the final boxed answers are:
\[
\boxed{f(x) \rightarrow \infty \text{ as } x \rightarrow \infty}
\]
\[
\boxed{f(x) \rightarrow -\infty \text{ as } x \rightarrow -\infty}
\]