In △ABC, points D on AB and E on AC are chosen such that AD=(x−2) cm, DB=(2x+1) cm, AE=(3x−4) cm and EC=(5x−9) cm.
(i) Derive the condition on x for which DE will be parallel to BC.
(ii) For the value x=5, determine whether DE is parallel to BC. Show all steps clearly and explain any inconsistency you observe.