Đáp án:
$\begin{array}{l}
a)x - \dfrac{{2x + 1}}{2} - \dfrac{{x + 2}}{3} > 1\\
\Rightarrow \dfrac{{6x - 3\left( {2x + 1} \right) - 2\left( {x + 2} \right)}}{6} > 1\\
\Rightarrow \dfrac{{6x - 6x - 3 - 2x - 4 - 6}}{6} > 0\\
\Rightarrow - 2x - 13 > 0\\
\Rightarrow x < \dfrac{{ - 13}}{2}\\
Vậy\,x < \dfrac{{ - 13}}{2}\\
b)\left( {2x + 3} \right)\left( {2x - 1} \right) < {\left( {2x - 5} \right)^2}\\
\Rightarrow 4{x^2} - 2x + 6x - 3 < 4{x^2} - 20x + 25\\
\Rightarrow 4{x^2} + 4x - 3 - 4{x^2} + 20x - 25 < 0\\
\Rightarrow 24x - 28 < 0\\
\Rightarrow 24x < 28\\
\Rightarrow x < \dfrac{7}{6}\\
Vậy\,x < \dfrac{7}{6}
\end{array}$
