Answer:
The last one
Step-by-step explanation:
[tex]x^3+1=0[/tex]
Subtract 1 from both sides
[tex]x^3+1-1=0-1[/tex]
simplify
[tex]x^3=-1[/tex]
[tex]\mathrm{For\:}x^3=f\left(a\right)\mathrm{\:the\:solutions\:are\:}x=\sqrt[3]{f\left(a\right)},\:\sqrt[3]{f\left(a\right)}\frac{-1-\sqrt{3}i}{2},\:\sqrt[3]{f\left(a\right)}\frac{-1+\sqrt{3}i}{2}[/tex]
[tex]x=\sqrt[3]{-1},\:x=\sqrt[3]{-1}\frac{-1+\sqrt{3}i}{2},\:x=\sqrt[3]{-1}\frac{-1-\sqrt{3}i}{2}[/tex]
simplify
[tex]x=-1,\:x=\frac{1}{2}-i\frac{\sqrt{3}}{2},\:x=\frac{1}{2}+i\frac{\sqrt{3}}{2}[/tex]
(That's basically the last one but in a different way of writing it)
