Помогите решить номер 3 умоляю

$1) \frac{2x + 5}{ {x}^{2} + 4x + 4} = \frac{2x + 5}{ {(x + 2)}^{2} } \\ \frac{2x + 5}{ {(x + 2)}^{2} } - \frac{x + 3}{x(x + 2)} = \frac{x(2x + 5)}{ x( {x + 2)}^{2} } - \frac{( x + 3)(x + 2)}{x {(x + 2)}^{2} } = \\ \frac{ 2 {x}^{2} + 5x - ({x}^{2} + 5x + 6 )}{x( {x + 2)}^{2} } = \frac{ {x}^{2} - 6}{x( {x}^{2} + 4x + 4)}$
$2) \frac{ {x}^{2} - 6 }{x( {x + 2)}^{2} } \times \frac{ { x }^{3} - 4x }{ {x}^{2} - 6 } = \frac{ {x}^{3} - 4x}{x {(x + 2)}^{2} } = \frac{x( {x}^{2} - 4 ) }{ x( {x + 2)}^{2} } = \frac{( x - 2 ) (x + 2)}{ ( {x + 2)}^{2} } = \frac{x - 2}{x + 2}$
x-2/x+2=x-2/x+2
Тождество доказано.