3х в квадрате -2х-5 больше нул

3х² - 2х - 5 ≻ 0D= 4 + 60 = 64          2 + 8         10         5x1 = ------------ =  -------- = -------            6              6          3        2 - 8x2= ----------- = -1           6      +              -                 +-----------◯-------------◯------------->            -1              5/3                     Ответ: ( -∞ ; -1 ) ⋃ ( 5/3 ; +∞ )