6. Calculate at \(x=7\):

\((x-4)^{(x-5)^{(x-6)}}{ }^{(x+6)^{(x+5)}}\)

Translate the above text into English, please retain the original text's line breaks and format, and output the translation result directly. 

6. Calculate at \(x=7\):

\((x-4)^{(x-5)^{(x-6)}}{ }^{(x+6)^{(x+5)}}\)
6. When \(x=7\), the given expression equals \(3^{2^{1}}=9\).