$$\frac { a } { 2 x + 1 } + \frac { 1 } { x + 2 } = \frac { 4 x + 5 } { 2 x ^ { 2 } + 5 x + 2 }$$
$x\in \mathrm{C}\setminus -\frac{1}{2},-2$
$a=2$
$a=2$
$x\neq -\frac{1}{2}\text{ and }x\neq -2$
$x\in \mathrm{R}\setminus -\frac{1}{2},-2$
$a=2$
