How can doubling a known fact be helpful when finding products mentally

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.

Find solution of the linear equation y = 2/3x + 1/3

Find the distance between c and d on the number line c=3 and d=11