Answer:
The total number of unbroken / working slots
Explanation:
Given that Devin's DVD case has 3 rows of slots, but 5 slots are broken
Also given that the number of slots in a row is x
1 row has x slots
3 rows has y slots
on cross multiplication we get y = 3x
ie there are a total of 3x slots in the 3 rows
Given that out of these 3x slots 5 . of the slots are broken
Therefore the total number of working slots = total number of slots - number of slots which are broken
total number of working slots are = 3x - 5
Therefore the given expression is the number of working / good slots