Quadratic formula since this trinomial is not factorable.
[tex] \frac{ - b + - \sqrt{ {b}^{2} - 4ac } }{2a} \\ \frac{ - 1 + - \sqrt{ {(1)}^{2} - 4(1)( - 1) } }{2(1)} \\ \frac{ - 1 + - \sqrt{1 + 5} }{2} \\ \frac{ - 1 + - \sqrt{6} }{2} \\ x = \frac{ - 1 + \sqrt{6} }{2} \\ x = \frac{ - 1 - \sqrt{6} }{2} [/tex]