Question

x в квадрате -2x- 1=0

Answer 1

$x^2-2x-1=0$
Дискриминант:
$D= sqrt{b^2-4ac}= sqrt{4+4}= sqrt{8}= 2sqrt{2}$

Корни:
$x_1= frac{2+2sqrt{2} }{2}= frac{2(1+ sqrt{2})}{2}= 1+ sqrt{2}$
$x_2= frac{2-2sqrt{2}}{2}= 1- sqrt{2}$