3. Consider the model with the following "definitions"of point,line, and incidence. A point is any pair of real numbers(x,y) such that x and y are not both sern. A line is a set of points (x,y) for which there are real numbers a and b not both set o such that either (x-n)² + (y-b)² = a² + b² or ax = by. In other words a line in any circle or straight line passing through the origin. A point in incident with a line if it satisfies the corresponding equation of the line.

Show that L1 holds for this model.