Answer: 
Step-by-step explanation:
You can use the following formula:

You can say that "T" is the time (in minutes) for both faucets working together, "A" is the time (in minutes) for cold water faucet working alone and "B" is the time (in minutes) for hot water faucet working alone.
Based on the data given in the exercise, you can identify that:

Therefore, substituting these values into the formula and solving for "B", you get that this is:

Answer:
x=3.5
Step-by-step explanation:
Y = x-3
Basically you just need to plug in an x value and solve for y
y = x - 3
y = (4) - 3
y = 1
In this case, the ordered pair of this equation would be (4, 1)
You can do this given any x or y coordinate
Hope this helps
I think A since working backwards and looking for a pattern wouldn't help, maybe C but im not sure