X + 5/6 = 2 2/3 CAN YOU GUYS PLS TELL ME WHAT IS X

What is the axis of symmetry of the function f(x)=-(x+ 9)(x-21)

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.

How many and of which kind of roots does the equation f(x)=x3−x2−x+1