First of all, I'm going to assume that we have a concave down parabola, because the stream of water is subjected to gravity.
If we need the vertex to be at
, the equation will contain a
term.
If we start with
we have a parabola, concave down, with vertex at
and a maximum of 0.
So, if we add 7, we will translate the function vertically up 7 units, so that the new maximum will be 
We have

Now we only have to fix the fact that this parabola doesn't land at
, because our parabola is too "narrow". We can work on that by multiplying the squared parenthesis by a certain coefficient: we want

such that:
Plugging these values gets us

As you can see in the attached figure, the parabola we get satisfies all the requests.
An equation written in slope-intercept form is y=mx+b, where m is a constant equal to the slope. Parallel lines have the same slope. So a line parallel to y=-2x+3 is y=-2x+5. Perpendicular lines have slopes which are negative reciprocals of each other. So a line perpendicular to y=-2x+3 is y=1/2x+7. y=2x-1 is neither parallel of perpendicular to y=-2x+3.
Answer:
15 units
Step-by-step explanation:
I just took this geometry test with the same question. Its 15
Answer:
x= 45
Step-by-step explanation:
x= -15*-3
x= 45