You have the vertex and y-intercept wrong.
Here is the model to follow:
f(x) = a(x - h)² + k
has:
vertex: (h,k)
axis of symmetry: x = h
y-intercept: (0,ah²+k)
Domain: all real numbers (-∞, ∞)
Range:
if a > 0, range is [k, ∞)
if a < 0, range is (-∞, k]
x-intercepts
a(x - h)² + k = 0
a(x - h)² = -k
(x - h)² = -k/a
____
x - h = ±Ö-k/a
____
x = h ± Ö-k/a
x intercepts are:
____
(x - h - Ö-k/a, 0)
and
____
(x - h + Ö-k/a, 0)
Now substitute the proper numbers for a, h, k, in all those.
[Don't let the clashing notation of h and h(x) confuse you,
they are not the same at all. To avoid confusion use H(x)
instead of h(x)].
Edwin
