Answer:

Step-by-step explanation:
First transpose 3x
you are having 3x+4y=7
by transposing you will get
4y=-3x+7
divide by 4 throughout by making y subject of the formula you will find your equation as y=mx+c.
I’m not sure I understand the question
48 gallons... since the first shower head gives 9 gallons per minute you multiply 9 by 8 then you use the equation and multiply 3 by 8 then you subtract the two shower heads
-5+-12 is -17
For lack of a better metaphor, it's like digging a pit deeper than it already is.