What is the equation of the line shown in this graph (-4, 1) (2, 1)

The points A(-4, 1) and B(2, 1) are contained in the line. Thus, this line is the horizontal line whose all points have the form (x, 1).

Whatever x is, y is always 1 for the points of this line. Thus, this is the line where y is always 1: this is the line y=1.

y=1