No, OD was (12, 9,-2). For CD, you had to consider the vector in the direction of BA, not AB. Hence, OC was (8 4 -8) and you add up OC and CD to get the position vector of OD.Okay yes, now I remember the answer. CD was ( -8 -4 8) and since OC was ( 4 5 6) then OD was ( -4 1 14)