Help me with this problem please

In the polynomial below, what number should replace the question mark to produce a difference of squares? x2 + ? x - 36

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.

Over the course of a month, a person's weight decreases. what type of relationship is this? a. positive relationship