Question

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Explanation:

Step1: Recall domain definition

The domain of a function is the set of all possible input (x) values for which the function is defined.

Step2: Analyze quadratic function graph

Quadratic functions are polynomials, and their graphs (parabolas) extend infinitely left and right along the x-axis, with no breaks, gaps, or restrictions on x-values.

Step3: Match to options

The only option that represents all possible x-values is "all real numbers".

Answer:

all real numbers