The domain of a quadratic function is the set of all possible input values (x-values) for which the function is defined. Since a quadratic function, such as \( y = x^2 + 2x - 24 \), is defined for all real numbers, the domain is:
\[ \text{Domain: } (-\infty, \infty) \]
This means that you can input any real number for \( x \) into the function.