# When finding the domain of a function or fraction.. is x cannot equal -3 and x cannot equal 5 the same as (-infinity,-3)union(-3,5)union(5,infinity)?

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You should remember that the domain of the function consists of all values that make the function to exist, hence, in the provided case, the function ceases to exist for `x=5` and `x=-3` , hence, these two values needs to be excluded from domain of definition.

Domain = `R - {-3 , 5}`

You may use the interval notation to write the domain of the function such that:

`(-oo,-3)U(-3,5)U(5,+oo)` (the symbol "U" represents the union)

**Hence, using the interval notation to write the domain of the function that is not defined at `x=-3` and `x=5` , yields `(-oo,-3)U(-3,5)U(5,+oo).` **

**Sources:**

I didn't understand what you were trying to say honestly. I only asked one question, if those mean the same thing and you didn't answer that. But thanks for your time anyway.