Question

Which graph represents a function

Answer 1

Answer:

Top left

Step-by-step explanation:

A function describe a relation between elements of a set (domain) to one and only one element of a second set (range). The key word is the "one and only one: it means that every time I put a value into the function (imagine it as a box) it returns either no value, or one value.

That lead us to the "vertical line test" or "ruler test". If you scan the images with a vertical line (you can use the edge of a piece of paper, a pen, whatever you want) and slide it across the plane, the moment you touch the graph in two (or more!) points, you can rule out that it's not a function. That's what happens with all graphs besides top left.

Answer 2

Answer:

The first one ( top left),

Step-by-step explanation:

All the other graphs fail the vertical line test.