Final answer:
The equation that models the number of bacteria in x hours is N = 9000 + 1000x. The doubling time is one hour.
Step-by-step explanation:
To find the equation that models the number of bacteria in x hours, we need to determine the rate at which the bacteria is growing. From the given information, we can see that the bacteria count increased from 9000 to 10000 after one hour. This means there was an increase of 10000 - 9000 = 1000 bacteria in one hour.
Since the bacteria count is increasing at a constant rate, we can say that the equation that models the number of bacteria in x hours is:
N = 9000 + 1000x
To find the doubling time, we need to determine the time it takes for the bacteria count to double. The doubling time can be found by dividing the total time taken for the bacteria count to double by the number of doubling cycles. In this case, the bacteria count doubled in one hour, so the doubling time is one hour.