Answer:
f(2)-f(1) => Difference between the count of bacteria between 11AM and 10AM
Step-by-step explanation:
Here x is the number of hours after 9AM
f(2) means the count of bacteria after 2 hours of 9AM i.e. at 11AM
f(1) means the count of bacteria after 1 hour of 9AM i.e. at 10 AM
f(2) - f(1) will give us the difference between the count of bacteria between 11 AM and 10 AM
Hence,
f(2)-f(1) => Difference between the count of bacteria between 11AM and 10AM