p4_2 v7/9. p2.7 t9.1. t6_7 t9_8. t7.1 t8_7. p2/2. v9/7. p2_8 v7.5. p8_5 t7_6. tg5_6 t6_5. t7_6. 1_0. cac ban thay toi giai the nao