Let the roots of the equation x3 – ax2 + bx – c = 0 be (α – 1), α, (α + 1) ∴ S2 = (α – 1)α + α(α + 1) + (α + 1) (α – 1) = b ⇒ α2 – α + α2 + α + α2 – 1 = b ⇒ 3α2 – 1 = b ∴ Minimum value of b = – 1, when α = 0.