Question 612537
The area of the den floor is 9*11 = 99 square feet


The area of the rug is 6*8 = 48 square feet


So the area that is NOT covered by the rug is 99 - 48 = <font color="red">51 square feet</font>


So there must be a typo somewhere, or there must be more to the problem (maybe the den is shaped in a different way?)