Answer:
y = -4
Step-by-step explanation:
A line with slope zero is a horizontal line. All points on a horizontal line have the same y-coordinate.
The equation of a horizontal line is
y = k,
where k is the y-coordinate of every point on the line.
Since we are told this line passes through the point (1, -4), and the y-coordinate of (1, -4) is -4, then every point on the line has y-coordinate -4.
The equation is
y = -4
