Question

Решите, пожалуйста! Очень надо!

Answer 1

$x + 4 = \frac{20x + 7}{x} \\ x(x + 4) = 20x + 7 \\ x {}^{2} + 4x - 20x - 7 = 0 \\ x {}^{2} - 16x - 7 = 0 \\ d = ( - 16) {}^{2} + 4 \times 7 = 256 + 28 = 284 = 2 \sqrt{71} \\ x _{1} = \frac{16 - 2 \sqrt{71} }{2} = 8 - \sqrt{71} \\ x_{2} = \frac{16 + \sqrt{71} }{2} = 8 + \sqrt{71}$