Đáp án:
$\begin{array}{l}
1)dkxd: - 2x + 3 \ge 0 \Rightarrow x \le \frac{3}{2}\\
2)Dkxd:\frac{2}{{{x^2}}} \ge 0 \Rightarrow x \ne 0\\
3)Dkxd:\frac{4}{{x + 3}} \ge 0 \Rightarrow x + 3 > 0 \Rightarrow x > - 3\\
4))Dkxd:\frac{{ - 5}}{{{x^2} + 6}} \ge 0 \Rightarrow {x^2} + 6 < 0\left( {ktm} \right)\\
= > x \in \emptyset \\
5)Dkxd:3x + 4 \ge 0 \Rightarrow x \ge - \frac{4}{3}\\
6){x^2} + 1 \ge 1 > 0\forall x\\
7)DKxd:1 - 2x > 0 \Rightarrow x < \frac{1}{2}\\
8)3x + 5 < 0 \Rightarrow x < - \frac{5}{3}
\end{array}$
