In general , any line parallel to

2y = -x+ 8 (Subway N )

y = (-1/2)x + 4

y= (-1/2)x + k , where k does not = 4

so it is not the same as Subway N

y = -0.5x + b, where b is any real number except 2

y= (-1/2)x

It has the same slope as the parallel equation, and it completes the rectangle.