Final answer:
To evaluate log9 81, we need to find the exponent to which 9 must be raised to obtain 81, which is 2.
Step-by-step explanation:
To evaluate the expression log9 81, we need to determine the exponent to which 9 must be raised to obtain 81. In other words, we need to find x such that 9^x = 81. Since 81 is equal to 9^2, we can conclude that the exponent x is equal to 2. Therefore, log9 81 = 2.