\[\left\{ \begin{matrix} a_{2} + a_{6} = 14 \\ a_{3} \cdot a_{5} = 45\ \ \\ \end{matrix} \right.\ \]
\[a_{2} + a_{6} = a_{1} + d + a_{1} + 5d =\]
\[= \left( a_{1} + 2d \right) + \left( a_{1} + 4d \right) =\]
\[= a_{3} + a_{5}\]
\[\left\{ \begin{matrix} a_{3} + a_{5} = 14 \\ a_{3} \cdot a_{5} = 45\ \ \\ \end{matrix} \right.\ \]
\[a_{3} = 9;\ \ a_{5} = 5\ \ или\ \ a_{3} = 5;\ \ \ \]
\[a_{5} = 9\]
\[Прогрессия\ возрастающая \Longrightarrow\]
\[\Longrightarrow a_{3} = 5;\ \ a_{5} = 9.\]
\[d = \frac{a_{5} - a_{3}}{5 - 3} = \frac{9 - 5}{2} = \frac{4}{2} = 2\]
\[a_{1} = a_{3} - 2d = 5 - 2 \cdot 2 =\]
\[= 5 - 4 = 1\]
\[Ответ:1.\ \]