Question

Решите уравнение
x^2 -2x -1 = 0

Answer 1

D=b^2-4ac=4+4=8   sqrt 8

x1 = (2+sqrt8)/2

x2= (2-sqrt8)/2

Answer 2

x^2 - 2x -1 = 0

Δ = b^2 - 4ac = 4 + 4*1 = 8
√Δ = 2√2

x1 = (2+2√2) / 2 = 1 + √2
x2 = (2-2√2)/2 = 1 - √2

ОТВЕТ:
 1± √2