\[- 4;\ - 6;\ - 8;\ - 10,\ \ldots;\]
\[d = - 6 + 4 = - 2;\]
\[a_{n} = a_{1} + d(n - 1) =\]
\[= - 4 - 2 \cdot (n - 1) =\]
\[= - 4 - 2n + 2 =\]
\[= - 2 - 2n;\ \ \]