The function is in vertex form of a quadratic function.
Vertex form is f(x)=a(x-h)^2+k
The vertex is (h, k)
In this case, our vertex is (2, 2). The a value is positive which means that the graph points up. Since the graph points up, the vertex is the minimum, the lowest point of the graph. The range refers to y-values, so the range of the function is y/y>2. It can also be written as 2≤y≤positive infinity.