Answer:
Each x value occurs only once
Step-by-step explanation:
In order for something to be classified as a function, it must pass the vertical line test, meaning a vertical line should never hit 2 points on the function, meaning each x value appears once. Y values can occur as many times, as long as each x value occurs once, it is a function. In this case, a y value appears 2 times, but each x value only does so once.
