How many points are needed to determine a unique line?
How many lines in L pass thru (1,1)?
Let L denote the set of straight lines through the origin in . Let M denote the set of straight lines through (1,1) in . How many elements does have?
Is this just how many times the lines intersect? If so is it not just LxM intersections including the origin and (1,1), or, (LxM)-2 not including the origin of (1,1)?