Решите неравенство (2х+1)(х-1)> 9
(2x + 1)(x - 1) > 9 2x² - 2x + x - 1 - 9 > 0 2x² - x - 10 > 0 D = 1 + 4*2*10 = 81 x₁ = (1 - 9)/4 x₁ = - 2 x₂ = (1 + 9)/4 x₂ = 2,5 _____+___________-________________+______ - 2 2,5 x ∈ ( - ∞ ; - 2) (2,5 ; + ∞)