(2x +1) * (x - 1)² - 5(2x + 1) = 0
(2x + 1)[(x - 1)² - 5] =0
(2x + 1)(x² - 2x + 1 - 5) = 0
(2x + 1)(x² - 2x - 4) = 0
или 2x + 1 = 0 и тогда 2x = - 1 x₁ = - 0,5
или x² - 2x - 4 =0
D = (-2)² - 4 * (- 4) = 4 + 16 = 20 = (2√5)²
(2x +1) * (x - 1)² - 5(2x + 1) = 0
(2x + 1)[(x - 1)² - 5] =0
(2x + 1)(x² - 2x + 1 - 5) = 0
(2x + 1)(x² - 2x - 4) = 0
или 2x + 1 = 0 и тогда 2x = - 1 x₁ = - 0,5
или x² - 2x - 4 =0
D = (-2)² - 4 * (- 4) = 4 + 16 = 20 = (2√5)²