Answer:

Step-by-step explanation:
<span>5-x=12
Subtract 5 from both sides
-x=7
Divide -1 on both sides so that the only thing remaining is x alone
Final Answer: x= -7</span>
1 kilometer = 1000 meters so 12 kilometers = 12000 meters
10 laps (400 meters/lap) = 4000 meters
12000/4000 = 3
Answer: 3 days
Too long busy make it shorter
10,800 would be the best awnser for you