If a relation is a function, how many y-values can an x-value have?
Yes.
Practice makes perfect
For a relation to be a function, each x-value can only be paired with one y-value, but one y-value can be paired with multiple x-values. In a graph, we can check if each x-value has only one y-value by subjecting it to the Vertical Line Test.
On the given graph, there is no visible part where two points have the same y-value. Each vertical line passes through the graph at only one point, so the graph represents a function.