... ứ0,25ADbtngthcCụưsichocỏcs dng: 1 1 1 , ,a b cv 1 1 1 , ,ab bc ca: ( )33323 1 1 1 1 1 1 1 1 1 1 1 1 1 1 3 3a b c ab bc ca abc abcabcabcabc ổ ử + + + + + + + + + + + = ỗ ữ ố ứ0,56 (1 im)ADbt/thcCụưsicho3s ... ịI:tõmmtcungoitiptdinSABC0,25*OHKIlhỡnhchnht,nờnOI=HK= 1 3 33 2 6a a =Bỏnkớnhmtcu:2 2 21 6aR IA OI OA = = + =Chỳý:cõunykhiD khụnglm0,25Tacú: 1 1 1 1 1 1 1 1 1 1 1 1 1 1a b c a b c ab bc ca abc ổ ửổ ửổ ... )22 1 : 2 1C x y - + =v ( ) ( ) ( )2 22: 5 3 25C x y - + - =0,25 1 SGIODCVOTOPHYấNTRNGTHPTCHUYấNLNGVNCHNHTHITHIHCLN1NMHC2 012 ư2 013 Mụnthi:TON,KHIA,A 1 ,B,D(Thigianlmbi180phỳt,khụngkthigian...