\[3a - 1:\]
\[- 3 \cdot 3 < 3a < 2 \cdot 3\]
\[- 9 < 3a < 6\]
\[- 9 - 1 < 3a - 1 < 6 - 1\]
\[- 10 < 3a - 1 < 5\]