n = 120 * 2^(t-9)

Where t represents the number of hours after 9:00 am.

To find the number of bacteria at 8:00 am, we can substitute t=8 into the equation:

n = 120 * 2^(8-9)
n = 120 * 2^(-1)
n = 120 * (1/2)
n = 60

Therefore, there are 60 bacteria at 8:00 am.

To find the number of bacteria at 7:00 am, we can substitute t=7 into the equation:

n = 120 * 2^(7-9)
n = 120 * 2^(-2)
n = 120 * (1/4)
n = 30

To find the number of bacteria at 8:00 am, we substitute t=8 into the equation n = 120 * 2^(t-9).

First, we substitute t=8 into the equation:
n = 120 * 2^(8-9)

Then, we simplify the exponent:
n = 120 * 2^(-1)

The value of 2^(-1) is equal to 1/2:
n = 120 * (1/2)

Finally, we multiply 120 by 1/2:
n = 60

Therefore, the number of bacteria at 8:00 am is 60.