Thanks for the reply,  all I need now is to figure out which one from P1 and P2 is inverse,  definitely one of them is negative,  given that I know the original range from where I started my calculations,  it should be easy to work out the nearest point to one of the above points.
I understand that P1 could be a number like 600, then P2 could be a number like 50, having just 550 as their distance is enough on it's own if I can guess which one is my known scalar to solve one of the points.