Aparabola has its vertex at (2,2), and the equation is y=2.5. the equation that represents the parabola is?

If the vertex of a parabola is given, you can begin with this general equation:
(h,k) is the vertex
So given (2,2) is the vertex that can be substituted into the equation.
You also stated the parent formula is . This means a = 2.5.
I simply substituted the values into the general equation.
If you perform all possible operations, an alternative equation is 

Idon’t know actually i’m in 5th grade and don’t know