In quadratic equation ax^2 + bx + c = 0 or [ (x + b/2a)^2 – D/4a^2] If a > 0, minimum value = 4ac – b^2/4a at x = -b/2a. If a < 0, maximum value 4ac – b^2/4a at x= -b/2a. 6. If α, β, γ are roots of cubic equation ax^3 + bx^2 + cx + d = 0, then, α + β + γ = -b/a, αβ + βγ + λα = c/a, and αβγ = -d/a 7.. "/>