$$\overrightarrow{AB} + \overrightarrow{BC} - \overrightarrow{MC} + \overrightarrow{MD} - \overrightarrow{KD} = \overrightarrow{AC} + \overrightarrow{CM} + \overrightarrow{MD} + \overrightarrow{DK} = \overrightarrow{AM} + \overrightarrow{MK} = \overrightarrow{AK}$$
Ответ: $$\overrightarrow{AK}$$