Answer:
B
Step-by-step explanation:
Answer:
Hello!!
For question twelve, 
is an identity.
For question thirteen, 
has no solution.
Hope this helps!!
The graph line will drop down by 12. meaning your initial cost (without any labor and material costs) goes down by 12, since your unit is in thousands
The first pump empties half the pond in 3 hours, so in 1/6 that time (1/2 hour), it empties (1/6)·(1/2) = 1/12 of the pond.
The second pump empties the other 5/12 of the pond in that half hour, so has a pumping rate of (1/2 h)/(5/12 pond) = (6/5 h)/pond.
The second pump could do the entire job alone in 1 hour and 12 minutes.
