Question

Корень из 15-2x-x в квадрате

Answer 1

$\sqrt{15 - 2x - {x}^{2} } = 0 \\ 15 - 2x - {x}^{2} = 0 \\ d = { (- 2)}^{2} - 4 \times 15 \times ( - 1) = 4 + 60 = 64 \\ x1 = \frac{ - ( - 2) + \sqrt{64} }{2 \times ( - 1)} = \frac{2 + 8}{ - 2} = - 5 \\ x2 = \frac{ - ( - 2) - \sqrt{64} }{2 \times ( - 1)} = \frac{2 - 8}{ - 2} = 3 \\ otvet..x1 = - 5 \\ x2 = 3$