[tex]\displaystyle\\\\x=\sqrt{8-2\sqrt{15}}-\sqrt{8+2\sqrt{15}}\\\\x=\sqrt{5+3-2\sqrt{5}\sqrt{3}}-\sqrt{5+3+2\sqrt{5}\sqrt{3}}\\\\x=\sqrt{5-2\sqrt{5}\sqrt{3}+3}-\sqrt{5+2\sqrt{5}\sqrt{3}+3}\\\\x=\sqrt{\Big(\sqrt{5}\Big)^{2} -2\sqrt{5}\sqrt{3}+\Big(\sqrt{3}\Big)^{2}}-\sqrt{\Big(\sqrt{5}\Big)^{2}+2\sqrt{5}\sqrt{3}+\Big(\sqrt{3}\Big)^{2}}\\\\x=\sqrt{\Big(\sqrt{5}-\sqrt{3}\Big)^{2}}-\sqrt{\Big(\sqrt{5}+\sqrt{3}\Big)^{2}}\\\\x=\Big(\sqrt{5}-\sqrt{3}\Big)-\Big(\sqrt{5}+\sqrt{3}\Big)[/tex]
[tex]\displaystyle\\x=\underline{\sqrt{5}}-\sqrt{3}-\underline{\sqrt{5}}-\sqrt{3}\\\\x=-\sqrt{3}-\sqrt{3}\\\\\boxed{\bf x=-2\sqrt{3}}\\\\\text{a) Calculam pe x la puterea a 2-a.}\\\\x^2=\Big(-2\sqrt{3}\Big)^{\b2}=2^2\cdot 3=4\cdot 3=12\\\\\boxed{\boxed{\bf x^2=12}}[/tex]
[tex]\displaystyle\\\\b)\\\Big(x+2\sqrt{3}\Big)^{1996}=\Big(-2\sqrt{3}+2\sqrt{3}\Big)^{1996}=0^{1996}=0\\\boxed{\boxed{\Big(x+2\sqrt{3}\Big)^{1996}=0}}[/tex]
