... ố 7 ứ 0 ,25 0 ,25 0 ,25 0 ,25 22 2 ổ Shngtngquỏttrongkhaitrin ỗ x2 - ữ l x ứ ố (0,5im) 0 ,25 k C22k ( x2) 22 - k ổ 2 = C k ( )k x44 -3 k ỗ- ữ 22 -2 ố x ứ ỡ0 Ê k Ê 22 ù Tacú ớk ẻ Ơ k = 12, Vy,hsca ... B m ;1 m2 , C m ;1 m2 Do ú BC m m (t/m (**)) 0 ,25 0 ,25 0 ,25 0 ,25 0,5 iu kin x > (1) log 22 x log x 4log 22 x 2log x 22 t t log x 0 ,25 t Pt cú dng 4t 2t t 2 t log ... ) (b c )2 9(b c )2 (c a) 5ca 9(c a )2 2 a b2 a2 b2 a b Suy (b c )2 5bc (c a )2 5ca (b c )2 (c a )2 b c c a 0 ,25 (a b )2 c (a b ) 2 a b c ( a b) 2 2( a b) ...