In this question, we have to find the equation of the line that us perpendicular to the x axis and passes through (-15,8).
Now, a line on the x-axis always has y = 0. Similarly, a line that is parallel to x-axis with some height 'h' should pass through the point (x, h) where y coordinate is h. Its equation is y = h
In this question, the line passes through (-15, 8) and parallel to x-axis should have equation y = 8
Similarly, a line perpendicular to the x-axis, passing through the origin should have equation x = 0.
But, as the line passing through the point (-15, 8). Therefore, the equation of that perpendicular line would be x = -15.