Answer: Hello!
we know that in the first hour, we had 880 cells, and in the second hour we have 3520 cells. The first step is see how much the population changed in this one hour, this can be done by looking into the quotient:
3520/880 = 4
then the population of cells cuatriplied in one hour, and is safe to asume that every hour that pases, the population will catriplied again.
so if the populationat hour 1 is: 880
at hour 2 is: 4*880
at hour 3 is = 4*4*880 and so on.
This can be described with an exponential function as follows

where 880 is the initial population, and x is represents the hours.