\[\sqrt[4]{36^{\log_{6}5} - 5^{\log_{5}9}} =\]
\[= \sqrt[4]{\left( 6^{\log_{6}5} \right)^{2} - 5^{\log_{5}9}} =\]
\[= \sqrt[4]{5^{2} - 9} = \sqrt[4]{25 - 9} = \sqrt[4]{16} =\]
\[= \sqrt[4]{2^{4}} = 2.\]
\[Ответ:\ \ 2.\]