Answer:
C (-∞, ∞)
Step-by-step explanation:
The term "domain" refers to the set of all possible input values for a relation. Here, the function h(x) is defined for all possible values of x, so we say the domain is "all real numbers." When that is expressed as an inequality, it looks like ...
-∞ < x < ∞
When that is written in interval notation, it looks like ...
(-∞, ∞)
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Additional comment
Round brackets (parentheses) are used in interval notation when the end number is not included in the set. It corresponds to the use of < in the inequality notation. Square brackets [ ] are used when the end number is included in the set. For example, 1 ≤ x would be [1, ∞) in interval notation.
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The function h(x) is a first-degree (linear) polynomial function in x. Its graph is a straight line. Any polynomial will generally have a domain that is "all real numbers", because the value can be computed for any value of x.
On a graph, we say the domain is the horizontal extent of the graph. The term "range" is used to signify the vertical extent of the graph, or the set of function output values.
