[tex]\displaystyle\\
\text{In fotografia atasata pare sa fie ultima parte a rezolvarii in R a unei}\\
\text{ecuatii de gradul 3, care suna asa:}\\\\
\texttt{\bf Se da functia: }~f(x)=x^3+27x. ~~~\texttt{\bf Determinati punctele de }\\
\texttt{\bf intersectie ale graficului functiei cu axa Ox.}\\\\
\text{Rezolvare: }\\\\
x^3+27x=0\\\\
x(x^2+27)=0\\\\
x_1 = \boxed{0}\\\\
x^2+27=0 ~~\Longrightarrow~~x^2=-27 ~~\Longrightarrow~~x_{23}= \pm\sqrt{-27}~~\notin R \\\\
\Longrightarrow~~\boxed{\bf x = 0}
[/tex]
x = 0 este singura solutie reala.
