Lời giải:
$\sin (-2x+3)=\frac{-\sqrt{3}}{2}$
\(\Rightarrow \left[\begin{matrix} -2x+3=\frac{-\pi}{3}+2k\pi \\ -2x+3=\frac{4}{3}\pi +2k\pi \end{matrix}\right.\Rightarrow \left[\begin{matrix} x=\frac{\pi}{6}+\frac{3}{2}-k\pi\\ x=\frac{-2}{3}\pi +\frac{3}{2}-k\pi \end{matrix}\right.\) với $k$ nguyên.