It is a polynomial so the domain is all real numbers.
It is a quadratic with a positive lead coefficient so the graph is a parabola that is concave up. Hence the range is the half-open interval from the y-coordinate of the vertex to positive infinity.
Set the function equal to zero and solve for the two roots. You are guaranteed to have two real roots because the lead coefficient and the constant term have the opposite signs. (it cannot be a perfect square and the discriminant must be positive).
John
My calculator said it, I believe it, that settles it
