Bµi gi¶ng p2 sãng dõng http://clip.vn/swf/player.vn.swf?v=3.192&id=Daii&enablejs=true&h=http://clip.vn bµi tËp ¸p dông p1. http://clip.vn/swf/player.vn.swf?v=3.192&id=Daiv&enablejs=true&h=http://clip.vn