... - 6z + = d) í 12 x - 8y - 12z - = ì5 x + y - 5z - = c) í 3 x + 3y - 3z + = 3 x - y - z - 23 = f) í 3 x - y - z + 33 = · cắt · trùng ì2 x + my + 3z - = c) í ỵnx - y - z + = 3 x - 5y + mz - ... B(11; - 23; 17), C (1; 0;19) a) A(1; 2; -3) , B(0; 3; 7), C (12; 5; 0) c) A (3; -4; 7), B(-5; 3; -2), C (1; 2; -3) d) A(4; 2; 3) , B(-2;1; -1), C (3; 8; 7) e) A (3; -1; 2), B(1; 2; -1), C (-1;1; -3) f) ... B(2; 4; -1) a) A(2; 4; -1), B(5; 2; 3) d) A(4; -3; -3) , B(2;1; 5) e) A(2; -3; 5), B(4;1; -3) Bài a) c) e) c) I (3; -2;1), A(2;1; -3) c) A (3; -2;1), B(2;1; -3) f) A(6; 2; -5), B(-4; 0; 7) Viết...