#andy
\[\begin{array}{l}
y = 3\sin \left( {x + \frac{{3\pi }}{4}} \right) - 1\\
- 1 \le \sin \,\left( {x + \frac{{3\pi }}{4}} \right) \le 1\\
\Leftrightarrow - 3 \le 3\sin \left( {x\frac{{3\pi }}{4}} \right) \le 3\\
- 4 \le y \le 3\\
\Rightarrow \max \, = 2,\,Min = - 4
\end{array}\]