Answer:
7 - 9 + (9 - 5)^2 - 4 (-6/6) + 8 - 3×10
-4
Hello, you forgot to provide the graphs but anyway this problem can be solved without them. If you want a graph where y is increasing by 1/2 each time x increases by 1, then you want a general equation in the form of:

where c is any constant.
Assuming the value of 0 for c, notice that when x is 1, y is 1/2, and when x is 2, y is 1. Therefore 1/2 was increased for y upon increasing 1 for x.
ANSWER: The graph of

.
to get the equation of any straight line, we simply need two points off of it, let's use the ones in the picture below.

45000 x 4 = 180,000
180,000 * 5 = 900,000 ml in 5 days
1 liter = 1000 ml
900,000 / 1000 = 900 liters of water