2(x +4)-6(q/9)
The slash represents a division sign.
Hope this helps with your question;)
Answer:

Step-by-step explanation:
Volume of a rectangular pyramid is given as = 
Where,



Plug in the above values into the formula for volume of rectangular pyramid:



Volume of the rectangular pyramid = 
Sum/5 = 90
so Sum = 450 which should be divided by 6
450/6 = 75 as the real average.
If I am understanding the question, and assuming the living room is a rectangle, then the border should be 80 ft