... x x x x= - - = - + - = - - + + - 3 26 9 4x x x= - + - + 3 26 9 4y x x x= - + - + Tp xỏc nh: D = Ă o hm: 2 3 12 9y x xÂ= - + - Cho 210 3 12 9 0 3 xy x xxộ=ờÂ= - + - = ờ=ờở ... x  Â= - - + - - = - - + - = + - Cho (nhan) (loai)2 21 [0;2]0 ( 2) 0 2 02 [0;2]xxy e x x x xxộ= ẻờÂ= + - = + - = ờ= - ẽờở Ta cú, 1 2(1) (1 1 1)f e e= - - = - 0 2(0) ... 1; 2; 4)A B = - - uuur, ( 2;1; 3) A C = - uuur 2 4 4 1 1 2[ , ] ; ; ( 10; 5; 5) 0 , ,1 3 3 2 2 1A B A C A B Cổ ử - - - - ữỗữỗ= = - - - ạịữỗữỗ - - ữữỗố ứuuur uuurr khụng thng...