$\log _{7} 9+\log _{7} 4$

Step 1 ：Use the logarithm property: \(\log_{a} b + \log_{a} c = \log_{a} (b \cdot c)\)

Step 2 ：Apply the property to the given expression: \(\log_{7} 9 + \log_{7} 4 = \log_{7} (9 \cdot 4)\)

Step 3 ：Calculate the product: \(\log_{7} (9 \cdot 4) = \log_{7} 36\)

Step 4 ：Write the final answer: \(\boxed{\log_{7} 36}\)