Answer: Choice C [tex]\{x | x \in \mathbb{R}, \ x > 5 \}[/tex]
The open circle means we do not include the endpoint, hence the use of a greater than symbol. If we were to include the endpoint, then we'd have greater than or equal to. We can rule out choice B due to this reasoning.
The ray pointing to the right indicates we are talking about x values larger than 5, so we can rule out choice A and conclude the answer is C.
Side note: The notation [tex]x \in \mathbb{R}[/tex] is saying "x is a real number"
