Final answer:
The domain of the quadratic function f(x) = 2x^2 + 2x - 4 is all real numbers because polynomials of degree 2 produce real outputs for any real input.
Step-by-step explanation:
The domain of a quadratic function refers to the set of all possible input values (x-values) that the function can accept. Looking at the quadratic function given by f(x) = 2x^2 + 2x - 4, we can determine that it is a polynomial of degree 2. Since polynomials of this form will produce real outputs for every real input, the domain of this function is all real numbers. Therefore, the correct answer for the domain of the given quadratic function is all real numbers.