Alright. If a slope is negative it is going from right to left, the slope is -1/2 which means the slope is going up -1/2 and to the side -1. Also, the y-intercept is 4, which means the slope runs through the point (0,4). lets put this into the slope equation:
y=mx+b
y = -1/2x + 4
where m = slope
b = y-intercept.
If another line is running parallel, then it will have the same slope but a different y-intercept. Since the other line running parallel runs through the points (1, -5), it means that the y-intercept for this equation is -5.
y = -1/2x + 11/2
Last, a line running perpendicular will simply be the reciprocal of the line it is perpendicular to. Therefore the equation of the line perpendicular to the first line is
y = 2x + 12
