\[a_{1} = - 2;a_{2} = 1,2;\]
\[d = a_{2} - a_{1} = 1,2 + 2 = 3,2;\]
\[S_{25} = \frac{2a_{1} + d(n - 1)}{2} \cdot n =\]
\[= \frac{2 \cdot ( - 2) + 3,2 \cdot (25 - 1)}{2} \cdot 25 =\]
\[= \frac{- 4 + 3,2 \cdot 24}{2} \cdot 25 =\]
\[= \frac{( - 4 + 76,8) \cdot 25}{2} = \frac{72,8 \cdot 25}{2} =\]
\[= 36,4 \cdot 25 = 910.\]
\[Ответ:910.\]