Answer:

Step-by-step explanation:
A linear function has the following format:

In which a is the slope(rate of change) and b is the y-intercept, that is, the value of y when x = 0.
Rate of change of 3
This means that 
So

A solution at (6, 12).
This means that when x = 6, y = 12. So



The linear function is:

2001 gallons used in 5 days, so the average for one day is 2001/5=400.2 gallons.
4/10 and 4/100 are the same because all you had to do was multiply both the numerator and denominator by 10. It is still the same amount. Hope this helps!
Answer:
Solution in photo
Step-by-step explanation: