Explicație pas cu pas:
[tex]x1 = \frac{ - b + \sqrt{b {}^{2} - 4ac } }{2a} \\ x2 = \frac{ - b - \sqrt{b {}^{2} - 4ac } }{2a} [/tex]
[tex]x1= \frac{ - 2 + \sqrt{4 - 4(a {}^{2} } + 1)}{2(a {}^{2} + 1) } = \\ \frac{ - 2 + 2a }{2(a {}^{2} + 1) } = \frac{2(a - 1)}{2(a {}^{2} + 1)} = \frac{a - 1}{a {}^{2} + 1} [/tex]
[tex]x2 = - \frac{ a + 1}{a {}^{2} + 1} [/tex]