Expand: fx=x^4-blankx^3+blank x^2 + blank x- blank

How to do this , and can some one explain

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.

Let event a = you roll an even number on the first cube. let event b = you roll a 6 on the second cube. are the events independent or dependent? why?