thanks for posting your question to Brainmass.
Domain is the set of x values for which the function is defined.
In this function, any value of x will evaluate to a number. Thus the domain of the function is all the real numbers.
As for the range - this is the set of values y can get.
The function is a parbola. Since the coefficient of x^2 is negative, this function is concave down and has a maxima (The minimal value is minus infinity, just plug in x=infinity or x=-infinity and you'll see).
To calculate the maxima, we take the first derivative ...
The domain and range and x intercepts of a function are found.The solution is detailed and includes references.