Susan plans to use 120 feet of fencing to enclose a rectangular area for a garden. Which equation best models the area, y, of the rectangular garden that she creates if one side is x feet long?
Well we set the perimeter to 120 feet. This means that 2x+2y=120 Now we know the area of a rectangle is xy so we have to solve for both x and y in the perimeter equation.
2x=120-2y x=60-y
2y=120-2x y=60-x
Now we plug these values into our area equation A=xy to get: A=(60-y)(60-x)
