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.
I believe the ansr would be (-6,-4) I say this becuase if it's positive on the y axis the X axis will be negative and if it's being reflected the coordinates will be backwards. If this answer is wrong I'm truly sorry, but I hope this helps!
Answer:
y=mx+b
Step-by-step explanation:
that is the equation
Answer: C im pretty sure
Step-by-step explanation:
Use this link it explains it pretty well
https://www.calculatorsoup.com/calculators/math/mixednumbers.php
Just copy and paste the link