Answer: Choice C
[tex](-\infty, \infty)[/tex]
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Explanation:
The domain is the set of all allowed x inputs of a function.
For this function, the domain is the set of all real numbers. This is because we can replace x with any number we want. There isn't any worry about division by zero errors for instance. We also don't have to worry about square roots of negative numbers.
The set of real numbers can be represented by the interval [tex]-\infty < x < \infty[/tex] telling us x can span from negative infinity to positive infinity. We can't reach either endpoint.
That compound inequality then condenses to the interval notation [tex](-\infty, \infty)[/tex]. The use of parenthesis says to exclude the endpoint.
