well... looking at how to question is defining things.....i think this is a multiple choice question.....
Given:
"y" represents the population
"x" represents the number of years
duration = 2000 - 1990 = 10 years
population increase = 2700 - 1200 = 1500
Now,
It says linear equation........, So, we have to assume that every ten years the population increases by a fixed amount that is 1500 people every 10 years.
Now,
Every 10 years, the population increases by 1500
Every 1 year , the population increases by 1500 / 10
= 150
Now,
The equation in determining the population is:
y = 150x + 1200