Ответ: ↓

[tex] { - x}^{2} + 2y + 4.16 = 0 \\ D = {2}^{2} - 4 \times ( - 1) \times 4.16 = 4 + 16.64 = 20.64 \\ x1x2 = \frac{ - 2± \sqrt{20.64} }{2 \times 2} \\ x1x2 = \frac{ - 2 - \sqrt{20.64} }{4} \: ; \: \frac{ - 2 + \sqrt{20.64} }{4} [/tex]