\[A(5;\ - 3);B( - 3;\ 7);\frac{\text{AC}}{\text{BC}} = \frac{1}{3}:\]
\[Середина\ AB:\]
\[x = \frac{5 - 3}{2} = 1;\ \ \ \]
\[y = \frac{- 3 + 7}{2} = 2.\]
\[Середина\ AK:\]
\[x = \frac{5 + 1}{2} = 3;\ \ \]
\[y = \frac{2 - 3}{2} = - 0,5.\]
\[Ответ:\ \ (3;\ - 0,5).\]