\[0 < 10 - 5 \cdot (x - 1) < 5x\]
\[10 - 5 \cdot (x - 1) = 10 - 5x + 5 = 15 - 5x\]
\[0 < 15 - 5x < 5x\]
\[\left\{ \begin{matrix} 15 - 5x > 0\ \ \\ 15 - 5x < 5x \\ \end{matrix} \right.\ \Longrightarrow \left\{ \begin{matrix} - 5x > - 15\ \ \ \ \ \ \ \ \ \ \ \\ - 5x - 5x < - 15 \\ \end{matrix} \right.\ \]
\[\left\{ \begin{matrix} x < 3\ \ \ \ \ \ \ \ \ \ \ \ \ \ \\ - 10x < - 15 \\ \end{matrix} \right.\ \Longrightarrow \left\{ \begin{matrix} x < 3\ \ \ \\ x > 1,5 \\ \end{matrix} \right.\ \]
\[Ответ:2)\ (1,5;3).\]