Ответ:

[tex](x - \frac{1}{2} )(2x + 1) = 4 {x}^{2} - 1 \\ 2 {x}^{2} + x - x - \frac{1}{2} = 4 {x}^{2} - 1 \\ - 2 {x}^{2} = - \frac{1}{2} \\ 2 {x}^{2} = \frac{1}{2} \\ {x}^{2} = 1 \\ x = 1\\ х=-1[/tex]