Given the expression :
[tex]\frac{6^4}{6^6}[/tex]We need to find which expression is not equivalent to the given expression
So,
The value of the given expression will be as follows:
[tex]\frac{6^4}{6^6}=6^{\mleft\{4-6\mright\}}=6^{-2}=\frac{1}{6^2}=\frac{1}{36}^{}[/tex]so, the answer will be option D)
[tex]\frac{1}{6^3}[/tex]