The population of a small town in 1990 was 1,200 people, and the population in 2000 was 2,700 people. let x represent the number of years since 1990. let y represent the population. which linear equation represents this data?

Well... looking at how to question is defining thingsi 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