([tex] \sqrt{5}[/tex][tex]- \sqrt{2} )^{2} -( \sqrt{5}+ \sqrt{2})^{2}+4 \sqrt{10} -2=[/tex], aplicam binom pentru ambele ( formula = [tex](a+b) ^{2} = a^{2} +2ab+b ^{2} ,(a-b) ^{2} = a^{2} -2ab+b ^{2} [/tex] ) si obtinem [tex]5 - 2 \sqrt{10} + 2 + 5 - 2\sqrt{10}- 2 + 4\sqrt{10}- 2[/tex] , se simplifica 4[tex]\sqrt{10} -2\sqrt{10} -2\sqrt{10} [/tex] si ramane 10 +2 - 4 = 8
