c)
\frac{(6-11^{\frac{1}{2}})(6+11^{\frac{1}{2}})}{(\sqrt{6-\sqrt{11}}-\sqrt{6+\sqrt{11}})^2}=
=\frac{6^2-(\sqrt{11})^2}{6-\sqrt{11}-2*\sqrt{(6-\sqrt{11})(6+\sqrt{11})}+6+\sqrt{11}}=
=\frac{36-11}{6-\sqrt{11}-2\sqrt{36-11}+6+\sqrt{11}}=
=\frac{25}{12-2\sqrt{25}}=\frac{25}{12-10}=\frac{25}{2}=12,5
d)
[{(3-\sqrt5)^{\frac{1}{2}}+(3+\sqrt5)^{\frac{1}{2}}]^{-2}}*[(\frac{27}{8})^{\frac{1}{3}}-28^0]=
=(\sqrt{3-\sqrt5}+\sqrt{3+\sqrt5})^{-2}*(\sqrt[3]{\frac{27}{8}}-1)=
=\frac{\frac{3}{2}-1}{(\sqrt{3-\sqrt5}+\sqrt{3+\sqrt5})^2}=
=\frac{1,5-1}{3-\sqrt5+2*\sqrt{(3-\sqrt5)(3+\sqrt5)+3+\sqrt5}}=
=\frac{0,5}{6+2\sqrt{9-5}}=\frac{0,5}{6+2*2}=\frac{0,5}{10}=0,05
=1/20