Queremos a soma dos cubos das raízes, isto é:
[tex3]\alpha^3+\beta^3=(\alpha+\beta)\cdot(\alpha^2-\alpha\cdot \beta+\beta^2)\\
\alpha^3+\beta^3=(\alpha+\beta)\cdot((\alpha+\beta)^2-3\alpha\beta)\\
\alpha^3+\beta^3=(-1)\cdot((-1)^2-3\cdot(-3))\\
\alpha^3+\beta^3=(-1)\cdot(1+9)\\
\alpha^3+\beta^3=-10[/tex3]