Question

Resolva a equação do terceiro grau:
x^3-9x^2+26x-24 = 0

Answer 1

(x - 3)(x^2 - 6x + 8) = x^3 - 6x^2 + 8x - 3x^2 + 18x - 24 = x^3 -9x^2 + 26x - 24.
(x - 3)(x^2 - 6x + 8) = 0
x - 3 = 0
x = 3
x^2 - 6x + 8 = 0 (a = 1; b = -6 e c = 8)
delta = b^2 - 4ac = (-6)^2 - 4•1•8 = 36 - 32 = 4 => Vdelta = 2
x = (-b +/- Vdelta)/2a
x’ = (-(-6) - 2)/2 = (6 - 2)/2 = 4/2 = 2
x’’ = (-(-6) + 2)/2 = (6 + 2)/2 = 8/2 = 4
S = {2,3,4}