Evaluate the limits. $$g(x) = \begin{cases} 3 x + 6 & x < -7 \\ -21 & x = -7 \\ 3 x - 6 & x > -7 \end{cases}$$ Enter DNE if the limit does not exist.

1. $\displaystyle{ \lim_{x \to -7^-} g(x) = }$
2. $\displaystyle{ \lim_{x \to -7^+} g(x) = }$
3. $\displaystyle{ \lim_{x \to -7} g(x) = }$
4. $\displaystyle{ g(-7) = }$