Acity's population was 30,700 people in the year 2010 and is growing by 850 people a year. (a) give a formula for the city's population, upper p, as a function of the number of years, t, since 2010.

For this case, the first thing we must do is define a variable.

We have then:

t: number of years

P (t): number of people since 2010

We know that:

1) There were 30,700 people in the city

2) The population is growing at a rate of 850 people per year.

The equation modeling the problem is given by:

a formula for the city's population is:

3x + 4y -25 =0 represents the amount of change sianna should recieve