Răspuns :
[tex]\it a)\ \ x^2+x+1=0;\ \ a=1,\ \ b=1,\ \ c=1,\ \ \Delta=b^2-4ac=1-4=-3\\ \\ b)\ \ x^2-49=0 \Rightarrow x^2=49\Rightarrow \sqrt{x^2}=\sqrt{49}\Rightarrow |x|=7\Rightarrow x=\pm7\Rightarrow \\ \\ \Rightarrow x_1=-7,\ \ x_2=7[/tex]
[tex]\it a)\ \ x^2+x+1=0;\ \ a=1,\ \ b=1,\ \ c=1,\ \ \Delta=b^2-4ac=1-4=-3\\ \\ b)\ \ x^2-49=0 \Rightarrow x^2=49\Rightarrow \sqrt{x^2}=\sqrt{49}\Rightarrow |x|=7\Rightarrow x=\pm7\Rightarrow \\ \\ \Rightarrow x_1=-7,\ \ x_2=7[/tex]