Answer:
Vertical lines are not functions.(not functions )
Function with no arguments and no return value.
Function with no arguments and a return value.
Function with arguments and no return value.
Function with arguments and a return value.
Explanation:
The equations y = ± x and x 2 + y 2 = 9 are examples of non-functions because there is at least one -value with two or more -values. The vertical line test is a great way to visualize a violation of the definition of a function.