Answer:
f(x) = -2x^2 + 4
or
f(x) = -2(x+0)^2 + 4
Step-by-step explanation:
Vertex form is written as
f(x) = a (x-h)^2 + k
where h and k are (x,y) of the vertex
Start by plugging these two values into the equation
f(x) = a (x- (0) )^2 + 4
Simplify
f(x) = ax^2 + 4
Next plug in the values of the second point for ( f(x),y )
-4 = a(2)^2 + 4
Solve
-4= 4a +4
-8=4a
-2=a
Plug -2 in for a in the initial equation
f(x) = -2x^2 + 4
