Question

the westridge city planners track the city's population each year. this year, the population is 15,400. a large tech company just opened their headquarters in westridge, so the city planners expect the city's population to grow by about 5% each year. write an exponential equation in the form y=a(b)x that can model the population of westridge, y, x years after the arrival of the new headquarters.

Answer 1

Explanation:

so, from year 0 to year 1 after arrival the population grows by 5% (= factor 1.05).

as growth means the number of people before plus the additional 5%.

so, we multiply 15,400 by (1 + 0.05) or simply by 1.05.

and in year 2 after arrival we multiply that result again by 1.05.

which is the year 0 number multiplied by 1.05 × 1.05 or simply 1.05².

in year 3 after arrival that result gets multiplied by 1.05. or year 0 multiplied by 1.05×1.05×1.05 or simply 1.05³.

and so on, and so on.

so, we get an exponential function with starting value of 15,400 :

y = 15,400 × (1.05)^x

to calculate the local population x years after the arrival of the large company.

for x = 0 we get the starting value of 15,400.