Răspuns :
[tex]x^2=0,8 \\ \Rightarrow x=\sqrt{0,8}\approx0,89 \\ S=\{\approx0,89\}[/tex]
[tex] x^{2} = 0,8 =\ \textgreater \ x = \sqrt{0,8} =\ \textgreater \ x =0 , 2 \sqrt{2} [/tex]