Answer: yes
Step-by-step explanation: To determine if the given relation is a function, we use what is called the vertical line test.
In other words, if we can draw a vertical line that passes through more than one point on the graph of this relation, then it's not a function.
On the graph here, it's impossible to draw a vertical or straight up and down line the intersects more than one point.
So yes, this relation must be a function.