Afarmer has 80 meters of fencing to use to enclose a rectangular garden that has one side against a barn. let l represent the length of the rectangular garden \left(in meters\right) and let a represent the area of the rectangular garden \left(in square meters\right).
write a formula that expresses a in terms of l.
what is the maximum area of the garden?

At the county fair, animals are judged for the quality of their breeding and health. the animal pens are arranged in an array, with one animal in each pen. a barn can hold at most 10 rows of pens and at most 6 pens in each row, with room for people to walk around them. what different ways can the planners of the county fair arrange the pens for the horses and cows in the same barn?