Алексей -x^2 - 4x + 5 = 0 D = b^2 - 4ac = 16 + 20 = 36 x1 = -b - sqrt(D) = (4 - 6) / (2*(-1)) = 1 x2 = -b + sqrt(D) = (4 + 6) / (2*(-1)) = -5 -(x-1)(x+5) = 0