For a specific answer, you need to present one or more equations in the context of your question.
Generally, for continuous, linear function equations the domain and range will be all real numbers, except when the denominator becomes zero (0).
This video will help you to understand the basic concepts and methods for deriving the domain, range, and (some of the) interval notations used for non-continuous functions. https://www.khanacademy.org/math/algebra/algebra-functions/domain-and-range/v/domain-and-range-from-graphs
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