Answer:
All real numbers
Step-by-step explanation:
we have the function
This is a vertical parabola open upward
The vertex represent a minimum
Remember that
The domain of a function is the set of all possible values of x
The quadratic functions are continuous and defined for all real values of x.
therefore
The domain of the function f(x) is the interval (-∞,∞)
That means
All real numbers