The problem above can be modelled as shown in the graph below
At

, the height of the water from the ground is

A line parallel to the given one will have the same slope, 0.5. For the purpose here, it is convenient to start with a point-slope form of the equation, then simplify. For slope m and point (h, k), the equation of the line can be written as
... y = m(x -h) +k
We have m=0.5, (h, k) = (-9, 12), so the equation is ...
... y = 0.5(x +9) +12
... y = 0.5x +16.5
The Answer for "X" is going to be 25.63201, rounded to the nearest tenth would be 25.6.
I hope this helped :)
-64 + -4 = -68
That is because 64 + 4 = 68 and the negatives in this case are the same way as if it was all positive.