Each input should only have 1 output. Multiple inputs can have the same output, but one input can only correspond to a single output.
Also, if you graph the relation with the input as the x coordinate and output as the y coordinate, you can then conduct a verical line test. Anywhere you draw a vertical line, you should only intersect the curve one time.
yes because its not how much you walk if it is the same distance to the park, then yes. You walked the same distance to the park, however the dog ran more around, you were possibly following the dog so... yea.
If you create the graph and then plot the points you will get a depiction of the trapazoids. using this you will find that they have reflected over the x=3 line.
