Answer
The slope is undefined.
The line does not have a $y$-intercept.
See the graph below.
Work Step by Step
For a vertical line, its equation's form is always the following:
$x=a$, where $a$ is a constant.
Here, the equation $x=-4$ is exactly as described above with $a=-4$.
Therefore the line is vertical.
Recall that a vertical linehas an undefined slope, and that if the line itself is not the $y$-axis ($x=0)$, it has no $y$-intercept.
The given line is not the $y$-axis, therefore it does not have a y-intercept.
Every point that has an $x$-coordinate of $-4$ is on the line given in the exercise.
Therefore, in order to sketch the line we only have to find two points with this attribute.
For example, $(-4,0)$ and $(-4,1)$.
Plot these poins then connect them using a straight line.
Refer to the graph above.
