a,\(\left(\sqrt{27}-\sqrt{12}-\sqrt{108}-\sqrt{192}\right):\sqrt{3}\)

b,\(\frac{\sqrt{2}-\sqrt{6}}{1-\sqrt{3}}\frac{3+2\sqrt{7}}{1+\sqrt{3}}\)

c,(\(\sqrt{15-6\sqrt{6}}+\sqrt{33-12\sqrt{6}}\)

A=\(\frac{\sqrt{x}}{\sqrt{x}-1}-\frac{2}{\sqrt{x}+1}-\frac{2}{x-1}\)

\(\sqrt{7-4\sqrt{3}}+\sqrt{13-4\sqrt{3}}\)

\(\frac{7+\sqrt{7}}{1+\sqrt{7}}+\frac{7-\sqrt{7}}{1-\sqrt{7}}\)