HELP On a graph the y axis goes by 200’s while the x axis goes by 10’s, I’m given the first equation y=8x+400 and told the slope is 8 which is the same as 200/25, how is that so?

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.