To solve this problem, you must find the rate of population growth or the slope, and the y-intercept or the population of Wallingfried in 1984. Using the y2-y1 /x2-x1 formula for calculating slope and plugging in the given values for (x1,y1) and (x2,y2), the slope for this graph can be written as (44,800-38,500) / (14-5) which simplifies to a slope of 700. From here, you can use the slope to find the value of the y-intercept a few different ways: 1.- Plug the slope and given values for (x1,y1) or (x2,y2) into the y=mx+b equation to solve for b. OR 2.- multiply the slope by 5 years and subtract this number from the population in 1989 to find the population in 1984. Both methods should give you a value of 35,000 for the population in 1984. After substituting in the slope and intercept values in the y=mx+b equation you get the function y=700x+35000 which can be graphed to represent the population growth in the Wallingfried neighborhood since 1984.