If you start in the lobby, go down 5 floors, and then
go down one more floor, where are you ?
Are you not then 6 floors below zero ?
Subtract 8 from both sides
-n = -12
Divide by -1
Solution: n = 12
Based on your image, I will assume u meant: 
This means that x will have two solution sets, due to the absolute value.

Answer:
Step-by-step explanation:
I believe the surface area is 150 squared becuase 6x10x5/2= 150 squared
3rd tile first, then 1st tile, 4th tile, 2nd tile.