Срочно нужна помощь, заранее спасибо ❣️

4)
$\frac{(x + 1 {)}^{2} }{6} + \frac{(x - 1 {)}^{2} }{12} - \frac{ {x}^{2} - 1}{4} = 1 \\ \frac{ {x}^{2} + 2x + 1 }{6} + \frac{ {x}^{2} - 2x + 1}{12} - \frac{ {x}^{2} - 1}{4} = 1 \\ 2( {x}^{2} + 2x + 1) + {x}^{2} - 2x + 1 - 3( {x}^{2} - 1) = 12 \\ 2 {x}^{2} + 4x + 2 + {x}^{2} - 2x + 1 - 3 {x}^{2} + 3 = 12 \\ 2x + 6 = 12 \\ 2x = 12 - 6 \\ 2x = 6 \\ x = 3$