Answer
(a) $y=5$
(b) $y-5=0$
(c) Refer to the attached image below for the graph.
Work Step by Step
(a)
RECALL:
The equation of a horizontal line is $y=b$ where $b$ is the y-intercept. All the points in this line has a y-coordinate of $b$.
Thus, the equation of a horizontal line whose y-intercept is $5$ is $\color{blue}y\color{blue}=\color{blue}5$.
(b) The general equation of a line is $Ax + By + C = 0$, where A, B are not both zero.
Thus, the general form of the vertical line's equation is:
$y-5=0$
(c) To graph the line, plot the points (-2, 5), (0, 5), and (2, 5) then connect them using a line. (Refer to the attached image in the answer part for the graph)