we have

This is a vertical parabola open up, so the vertex is a minimum
we know that
The vertex form of a vertical parabola function is given by the formula

where
(h, k)----------> is the vertex of the function
In this problem
the vertex is the point (2,4)
The domain is all real numbers----------> interval (-∞,∞)
The range is the interval------------> [4, ∞)
using a graph tool
see the attached figure