I don't get it, the concept is to make a proof, but I'm so confused

Polynomial that can be factored as (3x-4)(3x+4)

Which expression is not a polynomial?

The diameter of a bacteria colony that doubles every hour is represented by the graph below. what is the diameter of the bacteria after 8 hours? graph of a curve passing through the points zero comma 1, one comma two, two comma four, and three comma eight