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