`64/169=(8/13)^x`
`=> (8/13)^2=(8/13)^x`
`=> x=2`
\(9^x:3^x=3\)
\(\Rightarrow3^{2x}-3^x=3\)
\(\Rightarrow3^x=3\)
\(\Rightarrow x=1\)
+) \(\left(\dfrac{8}{13}\right)^x=\dfrac{64}{169}=\left(\dfrac{8}{13}\right)^2\)
\(\Rightarrow x=2\)
+) \(9^x:3^x=3\)
\(3^{2x}:3^x=3\)
\(3^x=3\)
\(x=1\)