Answer: n = -2
Step-by-step explanation:
3n +2(n + 2) = 9n + 12
(simplify 2(n + 2)) =
3n + 2n + 4 = 9n + 12
(subtract 9n from both sides)
3n + 2n - 9n + 4 = 12
-4n + 4 = 12
(subtract 4 from both sides)
-4n = 8
(divide -4 from both sides)
n = -2
Answer: 1 hour 20 minutes
Step-by-step explanation:
Given : The old machine could shred a truckload of paper in 4 hours.
Rate of work done by old machine = 
The new machine could shred the same truckload in 2 hours.
Rate of work done by new machine = 
Let 't' be the time taken by both of them working together , then we have the following equation:-

Since 1 hour = 60 minutes
Then, 
Hence, it will take 1 hour 20 minutes to shred the same truckload of paper if Ron runs both shredders at the same time.
Answer:
x=−5
Step-by-step explanation:
x+12=7
Step 1: Subtract 12 from both sides.
x+12−12=7−12
x=−5
-1 and 16/25
Negative one and sixteen twenty-fifths