Найдите первый член и разность арифметической прогрессии, если: a_3+a_5=-2; a_7+a_10=4.

\[a_{3} + a_{5} = - 2\]

\[a_{1} + 2d + a_{1} + 4d = - 2\]

\[2a_{1} + 6d = - 2\]

\[2a_{1} = - 6d - 2;\]

\[a_{7} + a_{10} = 4\]

\[a_{1} + 6d + a_{1} + 9d = 4\]

\[2a_{1} + 15d = 4\]

\[2a_{1} = 4 - 15d;\]

\[- 6d - 2 = 4 - 15d\]

\[9d = 6\]

\[d = \frac{6}{9} = \frac{2}{3};\]

\[2a_{1} = - 6d - 2 = - 6 \cdot \frac{2}{3} - 2 = - 6;\]

\[a_{1} = - 3.\]