Вопрос:

Ответ:

\[a_{1} = - 0,3;\ \ a_{7} = 1,9:\]

\[a_{7} = a_{1} + 6d\]

\[- 0,3 + 6d = 1,9\]

\[6d = 2,2\]

\[d = \frac{22}{60} = \frac{11}{30}.\]