To solve this problem you must apply the proccedure shown below:
1. You have the following information given in the problem above:
- The room has square dimensions and it has been built with two pieces of sheetrock, a smaller one and a larger one.
2. Therefore, let's call
x: the smaller one.
y: the larger one.
3. Then, you have that the lenght of the wall is the sum of the smaller one and the larger one:
x+y
4. So, the area of the room is:
(x+y)(x+y)
(x+y)²
Therefore, the answer is: (x+y)²