1. which expression is a cubic polynomial?

Any expression that has x^3 anywhere in the formula :)

A polynomial is just a string of x's or y's with superscrips ^2 and ^3 etc...

^2 is square & ^3 is cube

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 : )