A 12 foot by 8 foot rug covers the hardwood floor of a room. The rug leaves a uniform strip of bare floor surrounding the rug. If the area of the room is twice the area of the rug, what is the expression for the length of the room?
If the border has width w, then
(12+2w)(8+2w) = 2*12*8
the length of the room is 12+2w = 96/(4+w)