\[\boxed{\text{891\ (891).\ }\text{Еуроки\ -\ ДЗ\ без\ мороки}}\]
\[AC = x;\ \ BC = y;\ \ AB = 8;\ \ \]
\[\ 0 < x < 8\]
\[C - середина\ \text{AB}\]
\[x + y = 8\ \ \]
\[y = 8 - x\]
\[Ответ:C(4;4).\]