Someone pls help I don’t know how ti do this

If cos(2x) = tan^2(y), show that cos(2y) = tan^2(x).

Which shows the graph of the solution set of 3y – 2x > –18?

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.