A petri dish contains cells of a certain strain of bacteria. Each bacterial cell in the dish divides in half approximately every 6 minutes. The curve of best fit that models the number of bacterial cells in the dish is given by the equation f(x) = 4.2 • 1.1x, where x represents the number of minutes and y represents the number of cells. Approximately how many bacterial cells will be in the petri dish after 30 minutes?