In which pairs of matrices does AB = BA? 1.) A = [1 0 -2 1] B=[5 0 3 2]
2.) A=[1 0 -1 2] B=[3 0 6 -3]
3.) A =[1 0 -1 2] B=[5 0 3 2]
4.) A=[1 0 -2 1] B=[3 0 6 -3]

Skew lines(segments) are lines(segments) in 3 dimensions that do not intersect the given segment and are not parallel to it.  ae, bf, eg, and fh are your skew segments.  i hope that : )