You can
put this solution on YOUR website!If you have a total of 400 feet of timber then you cannot have a patio length of 400 feet.
2L = 400 - 2W <-- so L=200-W
A=LW
=(400-2W)W <-- =(200-W)W
=4==W-2W^ <-- =200W - W^2
A= 2W^ - 400W <-- Area = -W^2+200W
Not sure what you mean by vertex form but the line of symmetry is at (-b/2a)
=-200/-2
=100
So a width of 100 and a length of 100 will use 400 feet of timber and have an area of 10000 square feet.