Use the properties of logarithms to evaluate each of the following expressions (a) $\ln e^{8}-7 \ln e^{3}=$ П (b) $\log _{6} 9+\log _{6} 4=\square$

Step 1 ：Given expressions are \(\ln e^{8}-7 \ln e^{3}\) and \(\log _{6} 9+\log _{6} 4\)

Step 2 ：Using the property of logarithms \(\ln e^{x} = x\), the first expression simplifies to \(8 - 7 \ln e^{3}\)

Step 3 ：Using the property of logarithms \(a \log_b x = \log_b x^a\), the first expression further simplifies to \(8 - 7*3\)

Step 4 ：Using the property of logarithms \(\log_b x + \log_b y = \log_b (x*y)\), the second expression simplifies to \(\log_6 36\)

Step 5 ：Using the property of logarithms \(\log_b b^x = x\), the second expression further simplifies to 2

Step 6 ：Final Answer: \(\ln e^{8}-7 \ln e^{3}=\) \(\boxed{-13}\) and \(\log _{6} 9+\log _{6} 4=\) \(\boxed{2}\)