Question

a house is 40 feet wide and 60 feet long a lady wants to use 260 feet of fencing to fence an area behind her house. the back of the backyard is 60x+2x and one side is 200-4x divided by 2. the back yard is a rectangle shape

Answer 1

so, add up the sides to make 260.
That will give you x, and thus the dimensions of the yard.