Problem $7.(10$ points$)$

Let

$f(x)=\{\begin{array}{cc}-2x,& x<mn>7</mn>\\ 1,& x=7\\ 2x,& x>7\end{array}$

Find the indicated one$-$sided limits of $f,$ and determine the continuity of $f$ at the indicated point. You should also sketch a graph of $y=f(x),$ including hollow and solid circles in the appropriate places.

NOTE: Type DNE if a limit does not exist.

$\underset{x{7}^{-}}{lim}f(x)=$

$\underset{x{7}^{}}{lim}f(x)=$

$\underset{x7}{lim}f(x)=$

$f(7)=$

$$

Is $f$ continuous at $x=7?$

$($YES$/$NO$)$

Note: You can earn partial credit on this problem.