[latex](frac{3}{sqrt{3}}+2sqrt{2})^2-12sqrt{frac{2}{3}}=(frac{3}{sqrt{3}})^2+2 cdot frac{3}{sqrt{3}} cdot 2sqrt{2}+(2sqrt{2})^2-12sqrt{frac{2}{3}}=\ =frac{9}{3}+frac{12sqrt{2}}{sqrt{3}}+8-12sqrt{frac{2}{3}}=3+12sqrt{frac{2}{3}}+8-12sqrt{frac{2}{3}}=11 in mathbb{N}[/latex] [latex](frac{1}{sqrt{18}-sqrt{8}})^{-1}=sqrt{18}-sqrt{8}=sqrt{9 } cdot sqrt{2}-sqrt{4} cdot sqrt{2}=3sqrt{2}-2sqrt{2}=sqrt{2}[/latex]
zad 2 [latex](frac{1}{sqrt{18}-sqrt{8}})^{-1}=(frac{1}{sqrt{9*2}-sqrt{4*2}})^{-1}= (frac{1}{3sqrt{2}-2sqrt{2}})^{-1}=(frac{1}{sqrt{2}})^{-1}=frac{sqrt{2}}{1}=sqrt{2}[/latex] zad 1 [latex](frac{3}{sqrt{3}}+2sqrt{2})^{2}-12sqrt{frac{2}{3}}=\ \ =frac{9}{3}+2*frac{3}{sqrt{3}}*2sqrt{2}+4*2-12sqrt{frac{2}{3}}=\ \ =3+frac{12sqrt{2}}{sqrt{3}}+8-12sqrt{frac{2}{3}}=\ \ =11+12sqrt{frac{2}{3}}-12sqrt{frac{2}{3}}=\ \ =11 in N[/latex]