Раскладываем на множители 7x^2 + 13x - 2 .... 7x^2 + 13x - 2 = 0 D = 13^2 - 4*7(-2) = 169 +56 = 225 √225 = 15 x_1 = (-13+15)/14 = 2/14 = 1/7 x_2 = (-13-15)/14 = -28/14 = -2 7x^2 + 13x - 2 = 7*(x - 1/7)(x + 2) = (7x - 1)(x + 2)