Given two lines in space, either they are parallel, they
intersect, or they are skew (lie in parallel planes). Determine
whether the lines below, taken two at a time, are parallel,
intersect or are skew. If they intersect, find the point of
intersection. Otherwise, find the distance between the two
lines.
L1: x=1-t, y=1-2t,z=2-2t, -infinity is less than t is less than
infinity
L2: x=-5-2s, y=-13-4s, z=2-4s, -infinity is less than s is less
than infinity
L3: x=1+2r, y=1+5r, z=2+r,...