Folosesti formula de calcul prescurtat
[tex] (a+b)(a-b)=a^{2}- b^{2} [/tex]
[tex] (1+\sqrt{5-\sqrt{3}}) (1-\sqrt{5-\sqrt{3}}) +(1-\sqrt{7+\sqrt{3}})(1+\sqrt{7+\sqrt{3}}) = \\
=1^{2}-(\sqrt{5-\sqrt{3}})^{2}+1^{2} - (\sqrt{7+\sqrt{3}})^2=\\=1-(5-\sqrt{3}) +1-(7+\sqrt{3})=1-5+\sqrt{3} +1-7-\sqrt{3}=-10 [/tex]