(x² - 2x - 1) 2 = 2x² - 4x - 2 2x² - 4x - 2 | : 2 x² - 2x - 1 = 0 D = b² - 4ac = 2² - 4 × 1 × (- 1) = 4 - (- 4) = 0 x₁,₂ = -b / 2a = 2 / 2 = 1 2 × 1² - 4 × 1 - 2 = - 4