Which is the correct simplified form of the expression

What is the product of the radical expression. (7-2square root) (8+2 square root)

What is the value of x in the diagram below?

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.