2. Bacteria is growing exponentially in a lab as shown in the table below. The researcher observes the number of bacteria in a sample beach hour after starting the sample. She writes a function to model the bacteria's growth in the form f(x) = ab where x represents the time since starting the sample. Hours, x 0 2 5 Population, f(x) 15 30 60 120 240 480 a. What is the value and the meaning of the variable a in the function modeling the bacteria's growth