Write the indicated function?

Question

Sue wants to put a rectangular garden on her property using 80 meters of fencing. there is a river that runs through her property so she decides to increase the size of the garden by using the river as one side of the rectangle. (Fencing is then needed only on the other three sides). Let x represent the lenghth of the side of the rectangle along the river. Express the garden's area as a function of x.

(best answer for 1st correct answer)

Answer 1

[(80-x)/2] (x)_