[tex] { \times 2 + \times + 1 = 0}^{?} [/tex]


Răspuns :

[tex]\it x^2+x+1=0 \Rightarrow x^2+x+\dfrac{1}{4}+\dfrac{3}{4}=\underbrace{\Big(x+\dfrac{1}{2}\Big)^2+\dfrac{3}{4}}_{>0}=0 \Rightarrow x\not\in\mathbb{R}[/tex]