What is the answer i do not know what ir is

What is the slope simplify your answer and write it as a proper fraction, improper fraction, or integer

Witch represents the inverse of the function f(x)=1/4x-12

David estimated he had about 20 fish in his pond. a year later, there were about 1.5 times as many fish. the year after that, the number of fish increased by a factor of 1.5 again. the number of fish is modeled by f(x)=20(1.5)^x. create a question you could ask that could be answered only by graphing or using a logarithm.