I need help this is my last question and my brain hurts plus I need a good grade too, thank you!

Step-by-step explanation:

We notice that x=0 is halfway between x = -1 and x = 1, so the corresponding y-intercepts will be ...

  for y1, (6+4)/2 = 5

  for y2, (12+16)/2 = 14

Each step in x is +2. The steps in y1 are -2, so the slope is -2/2 = -1.

The steps in y2 are +4, so the slope is 4/2 = 2.

Now, we have the slopes and intercepts, so we can write the system of equations as ...

  y1 = -x +5

  y2 = 2x +14

__

The y-values are shown as equal in the table for x=-3, so the solution of the system of equations is ...

  (x, y) = (-3, 8)

step-by-step explanation:

12: 00 p.m. to 7: 00 p.m. is a total of 7 hours.

4: 00 p.m. to 7: 00 p.m. is a total of 3 hours.

this means that from 4: 00 p.m to 7: 00 p.m. this represents 3/7 of what was lost from 12: 00 p.m. to 7: 00 p.m.

after knowing this, after doing 11,600 - 6,800 = 4,800

4,800 represents 3/7 of what was lost for 7 hours.

we then divide 4,800 by 3 which gets 1,600.

because we know that 1,600 represents 1/7 of how much water was lost, we just have to multiply by 7, which gets 11,200.   after adding 11,200 to how much water was left at 7: 00 p.m. which was 6,800. 11,200 + 6,800 = 18,000

this means that the pool originally had 18,000 gallons in the pool.

you can also check your work by doing 18,000 - 4(1600), which becomes           1800 - 6400 which gets you 11,600.