Evaluate the given limits using the graph of the function $f(x) = \displaystyle 2^x + 6$ shown above.

1. $\displaystyle \lim_{x \to -\infty} f(x)$ =
2. $\displaystyle \lim_{x \to \infty} f(x)$ =
3. $\displaystyle \lim_{x \to 0} f(x)$ =

See limit