\[\boxed{\mathbf{756}\mathbf{.}}\]
\[1)\ y = \arcsin\frac{x - 3}{2}\]
\[- 1 \leq \frac{x - 3}{2} \leq 1\]
\[- 2 \leq x - 3 \leq 2\]
\[1 \leq x \leq 5.\]
\[Ответ:\ \ x \in \lbrack 1;\ 5\rbrack.\]
\[2)\ y = \arccos(2 - 3x)\]
\[- 1 \leq 2 - 3x \leq 1\]
\[- 3 \leq - 3x \leq - 1\]
\[\frac{1}{3} \leq x \leq 1.\]
\[Ответ:\ \ x \in \left\lbrack \frac{1}{3};\ 1 \right\rbrack.\]
\[3)\ y = \arccos\left( 2\sqrt{x} - 3 \right)\]
\[- 1 \leq 2\sqrt{x} - 3 \leq 1\]
\[2 \leq 2\sqrt{x} \leq 4\]
\[1 \leq \sqrt{x} \leq 2\]
\[1 \leq x \leq 4.\]
\[Ответ:\ \ x \in \lbrack 1;\ 4\rbrack.\]
\[4)\ y = \arcsin\left( \frac{2x^{2} - 5}{3} \right)\]
\[- 1 \leq \frac{2x^{2} - 5}{3} \leq 1\]
\[- 3 \leq 2x^{2} - 5 \leq 3\]
\[2 \leq 2x^{2} \leq 8\]
\[1 \leq x^{2} \leq 4\]
\[\left\{ \begin{matrix} - 2 \leq x \leq - 1 \\ 1 \leq x \leq 2\ \ \ \ \ \ \ \\ \end{matrix} \right.\ \]
\(Ответ:\ \ x \in \lbrack - 2;\ - 1\rbrack \cup \lbrack 1;\ 2\rbrack.\)