The domain of a function is the two points on the left and right most sides of the graph. Domain is measured from left to right. The domain of this graph, by measuring the left most part to the right most part of the graph, would be:
8 ≤ x < ∞
Whenever an arrow is present, a continuous graph is what that represents.
Answer Recap: 8 ≤ x < ∞ is the domain of this function.
