H\u00ecnh h\u1ecdc – Ch\u01b0\u01a1ng 2 – B\u00e0i 3: \u0110\u01b0\u01a1\u0300ng th\u0103\u0309ng va\u0300 m\u0103\u0323t ph\u0103\u0309ng song song<\/a><\/blockquote><\/iframe>