Answer:
The graph opens up because the minimum value of the function is 4 and the function goes to infinity as x -> -∞, and as x -> +∞.
Explanation:
The given domain of x = (-∞, ∞).
Because the range of y = (4, ∞), there is a vertex at a value of (x, 4).
The function is of the form
y = a(x-h)² + 4
where
(h,4) is the vertex, for some value of x = h.
a is positive because the curve opens up.
