Determine whether each table or rule represents an exponential function. explain why or why not. x=1,3,4 y=3,9,27,81

Think of x as input and y as output. x can only have one y or output. Since there are more y's than x's, I would say it does not. There should be an equal amount of x (inputs) and y (outputs). This table would not be a function.

I hope this helps!
~cupcake