In order to plot point (5, 0), we start from the origin and move 5 cm along x- axis. The point we arrive at is point (5,0).
To plot point (5, 1), we move 5 cm along x- axis and 1 cm along y- axis. The point we arrive at is point (5,1).
To plot point (5,8), we move 5 cm along x- axis and 8 cm along y- axis. The point we arrive at is point (5,8).

After plotting points, we observe that all points are having same ordinate ( ie. same x-coordinate.)

Hence, all points lie on the same line.