Answer:
b. 4+7x-2
Explanation:
when you add like terms for the first equation it becomes 7x-6
the second one becomes 7x+2
the third one becomes 7x-6
and the last one is also 7x-6
which means the second one is not equivalent
Answer:
4.5 or 4.69 because you round it
Answer:
A. 1
Step-by-step explanation:
12x + 6 = 5x
12x - 5x = - 6
7x = - 6
x = - 6 / 7
Only one solution.
Answer:
18 hours
Step-by-step explanation:
The unit rate of intake pipe is
[1 tank in 6 hours]
The total unit rate (combined) when 2 work together is
[1 tank in 9 hours]
Intake fills up and outlet empties. Thus we can say:
Rate of Intake - Rate of Outlet = Combined Rate
This becomes:

Where x is the rate of outlet pipe [what we are looking for]
Doing algebra we solve for x:

This means "outlet pipe can empty 3 tanks in 54 hours". So that would mean 54/3 = 18 hours to empty 1 tank