The population of Nertonville was 7,960 in 2005 and it is growing at an annual rate of 2.5% .

Since the growth rate is 2.5% = 0.025, the growth factor is 1 + 0.025 = 1.025
y = population, x = number of years passed
y = initial * (growth factor)^x
y = 7960 * (1.025)^x

The y value (population) of each is increasing by 2.5% of the population from previous year.

There is no y-intercept because the population never starts at 0.