Answer
$y = -1+2~tan~x$
We can see the graph below.
Work Step by Step
$y = -1+2~tan~x$
When $x = -\frac{\pi}{2}$, then $y = -1+2~tan~(-\frac{\pi}{2})~~$ (which is undefined)
When $x = -\frac{\pi}{4}$, then $y = -1+2~tan~(-\frac{\pi}{4}) = -3$
When $x = 0$, then $y = -1+2~tan~0 = -1$
When $x = \frac{\pi}{4}$, then $y = -1+2~tan~\frac{\pi}{4} = 1$
When $x = \frac{\pi}{2}$, then $y = -1+2~tan~\frac{\pi}{2}~~$ (which is undefined)
We can see the graph below.