[tex] \frac{2x^{2} + x - 1}{ {x}^{2} - 1 } = 0 \\ \frac{2x^{2} + 2x - x - 1}{ (x - 1)(x + 1) } = 0 \\ \frac{2x ( x + 1) - (x + 1)}{ (x - 1)(x + 1) } = 0 \\ \frac{(x + 1)(2x - 1)}{(x - 1)(x + 1)} = 0 \\ \frac{2x - 1}{x - 1} = 0 \\ 2x - 1 = 0 \\ 2x = 1 \\ x = \frac{1}{2} [/tex]

або можна записати x = 0,5