The solid waste generated each year in the cities of the US is increasing. The solid waste generated, in millions...

The solid waste generated each year in the cities of the US is increasing. The solid waste generated, in millions of tons, was  in 1960 and  in 1980. The trend appears linear during this time. Consider that  is the difference of years ( represents 1960)

 

(a) Construct a formula for the amount of municipal solid waste generated in the US,  in millions of tons, in terms of the difference of years,  by finding the equation of the line through these two points.

 

Enter the exact answer.