Three times a number, minus 5 is equal to two times the number, plus 7

3x - 5 = 2x + 7 i call the number "x"
3x = 2x + 12
1x = 12
x = 12 the number is 12

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 : )