Final answer:
The growth of bacteria modeled by the function f(x) = 1.8x is best described as linear, as the rate of change is consistent. This does not reflect the actual exponential growth seen in bacterial populations, where the number of organisms accelerates over time.
Step-by-step explanation:
The function f(x) = 1.8x represents how a population changes with respect to some variable, often time. In the context of bacterial growth, the best description for the growth represented by this function is: bacterial growth is linear. This is because the rate of change (the coefficient 1.8) remains constant for each unit increase in x, which typically would be time. Therefore, for each hour or given time period, you'd expect a constant increase.
However, this model does not capture the exponential growth typically observed in bacteria populations where the growth rate accelerates over time. Instead, an exponential growth function for bacteria would look more like f(x) = C * 2^x, where C is the initial number of bacteria and x is the number of time intervals (like hours).