You can plot this by turning the fraction into a decimal. -1&1/3rds is -1.333... and 1/6ths is about .16, so then you can find these points on the number line. Also, the number line has 6 points equal one, so the points by those.
If there are no repeating x values and an x value only goes to <em>one</em><em> </em>y value, then yes, it is a function.
It would be 11 if I’m reading this right