Question

СРОЧНО СРОЧНО СРОЧНО​

Answer 1

$\frac{x + 1}{2x + 4} - \frac{2}{4 - {x}^{2} } - \frac{x - 1}{2x - 4} = \frac{(x + 1) \times (2x - 4)}{(2x + 4) \times (2x - 4)} - \frac{2 \times ( - 4)}{(4 - {x}^{2}) \times ( - 4) } - \frac{(x - 1) \times (2x + 4)}{(2x - 4) \times (2x + 4)} = \frac{2 {x}^{2} - 4x + 2x - 4}{4 {x}^{2} - 16} - \frac{ - 8}{4 {x}^{2} - 16 } - \frac{2 {x}^{2} + 4x - 2x - 4 }{4 {x}^{2} - 16} = \frac{2 {x}^{2} - 4x + 2x - 4 + 8 - 2 {x}^{2} - 4x + 2x + 4 }{4 {x}^{2} - 16} = \frac{ - 4x + 8}{4 {x}^{2} - 16} = - \frac{4(x - 2)}{4( {x}^{2} - 4)} = - \frac{x - 2}{(x - 2)(x + 2)} = - \frac{1}{x + 2}$

при $x = \frac{1}{2} ,$

$- \frac{1}{x + 2} = - \frac{1}{ \frac{1}{2} + 2 } = - \frac{1}{ \frac{1}{2} + \frac{4}{2} } = - \frac{1}{ \frac{5}{2} } = - 1 \times \frac{2}{5} = - \frac{2}{5} = - 0.4$