Parallel, intersecting or skew?
AB and BC.
AE and BF.
EF and AD.
Plane ABC and Plane ABF.
Plane AED and Plane BFC.
HELP!!!

Two lines are:

Parallel if they don't intersect and lie on the same planeIntersecting if...well, they intersect at one pointSkew if they don't intersect and they lie on two different planes

So, we have:

AB and BC intersect at point BAE and BF don't intersect, but both lie on the plane AEFBEF and AD don't intersect and don't lie on a common planeABC and ABF intersect on segment ABAED and BFC are parallel (they're both perpendicular to plane ABC)