B\u00e0i t\u1eadp tr\u1eafc nghi\u1ec7m H\u00ecnh h\u1ecdc 12 \u2013 B\u00e0i 2: Ph\u01b0\u01a1ng tr\u00ecnh m\u1eb7t ph\u1eb3ng (ph\u1ea7n 7)<\/a><\/blockquote><\/iframe>