^{_{Ta có : abc-cb=ab}}

^{_{Th1:b=0 (t/m)}}

^_Th2:

^{_{Vì a, b thuộc N nên}} 

^{_{a-1=1 và c-1=2}}

^{_{=>a=2 và c=3}}

^{_{❤ HOK TT ❤}}

^{_{6576-87654+99097=18019}}

_{16. B}

_{17. D}

_{18. D}

_{19. C}

_{20. D}

_{❤ HOK TT ❤}

^_1.C

^_2.C

^_3.C

^_4.A

^_5.C

^_6.D

^_7.D

^_8.D

^_9.A

^_10.D

^_11.B

^_12.A

^_13.A

^_14.A

^_15.B

^{_{❤ HOK TT ❤}}

^{_{4. His friend asked him how he went to the airport.}}

^{_{5. She asked Hoa where she learnt English.}}

^{_{6. The teacher asked me what aspect of learning English the students found most difficult.}}

^{_{7. He asked what time schools began.}} 

^{_{❤ HOK TT  ❤}}

_{42.The mother told her son to move there.}

_{hok tt}