[tex]\bf{ \frac{ - 4}{2x + 1 } \geqslant 0 < = > - \frac{4}{2x + 1} \geqslant 0 }[/tex]
[tex]\bf{ \frac{1}{2x + 1} \leqslant 0}[/tex]
[tex]\bf{2x + 1 < 0 \: \: < = > \: \: 2x < - 1}[/tex]
[tex]\bf{x < - \frac{1}{2} \Rightarrow \: x \in ( - infinit , - \frac{1}{2}) }[/tex]
