Answer:
y= -1/9(x-1)^2 +2
Explanation:
The vertex is at (1,2) and another point is at (-2,1).
We know the vertex form of a parabola is
y= a(x-h)^2 +k where (h,k) is the vertex
Substituting the vertex in
y= a(x-1)^2 +2
We have another point, (-2,1)
Substitue this in with x=-2 and y =1. This will let us find a
1 = a(-2-1)^2 +2
1 = a (-3)^2 +2
1 = a*9 +2
Subtract 2 from each side
1-2 = 9a +2-2
-1 = 9a
Divide by 9
-1/9 = 9a/9
-1/9 =a
Putting this back into the equation
y= -1/9(x-1)^2 +2