Answer:
Hi! I hope this answer helps you.
In mathematics, the vertical line test is a visual way to determine if a curve is a graph of a function or not. A function can only have one output, y, for each unique input, x.
any vertical line in the plane can intersect the graph of a function at most once.
HOW TO DO THIS
take your pencil and place it on your paper vertically (up and down direction)
move the pencil across the paper to the right
if the pencil crosses more than two points on the line it is not a function
the first problem would be a function
the second problem would be a function
the third problem would not be a function
hope this helps !!!!
