Well...if the coordinates of the point can be plugged into the equation of the line, and it works, then the point is on the line.
For example, point (1,6) is on the line y=3x+3.
Plug the coordinates in:
So point (1,6) is on the line y=3x +3
Or you could locate the point on the line in a graph...
Is this image too big? I used https://www.desmos.com/calculator to graph.
Correct me if my answer is wrong.