theo toi khong the di c3 tan1 hay c3 binh 4 duoc
m5/3;s6/5;den ko the an ph hay m do duoc vi co c3-4 hoac c3tan1;

m3 tan 4;m2 thoai 4 an m'p4-4 chieu tuong m4tan 6;chot3-4;tuong 6 binh 5;chot 4binh 5;tuong 5 binh 4,chot 5 tan 1 het co... chac la dung