\[1)\ B(5;\ 4),\ \ \ C(3;\ 2):\]
\[x = \frac{5 + 3}{2} = \frac{8}{2} = 4;\]
\[y = \frac{4 + 2}{2} = \frac{6}{2} = 3.\]
\[Ответ:\ \ (4;\ 3).\]
\[2)\ B( - 2;\ - 1),\ \ \ C( - 1;\ 7):\]
\[x = \frac{- 2 - 1}{2} = - \frac{3}{2} = - 1,5;\]
\[y = \frac{- 1 + 7}{2} = \frac{6}{2} = 3.\]
\[Ответ:\ \ ( - 1,5;\ 3).\]