What is the domain of f(x)=x2−9x−3f(x) = \frac{x^2 - 9}{x-3}f(x)=x−3x2−9?
(−∞,∞)(-\infty, \infty)(−∞,∞)
All real numbers except x=3x=3x=3
All real numbers except x=3,−3x=3, -3x=3,−3
[3,∞)[3, \infty)[3,∞)