The document discusses using an equation to model population growth in the United States between 2010 and 2050. It states that the 2010 population was 300 million and is expected to increase by 2.5 million per year. An equation is provided to calculate the population P in any given year x: P = 2.5x + 300. Using this equation, the document determines that the predicted population in 2050 is 400 million.