Please help i really need help on this homework

Identify a1 and r for the geometric sequence an= -256(-1/4) n-1

Determine the difference: 3.2 × 1010 – 1.1 × 1010. write your answer in scientific notation.

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.