Function Machines

1. If an input of $-9$ is put into each of the machines at right, what is each output?

   Hint(a):

   Substitute $-9$ for $x$ in each of the equations in both the machines, then solve the equations for $y$.

2. Eric wants to get an output of $0$. Can he do this with each machine? If so, how? If not, why not?

   Hint(b):

   What numbers could Eric substitute in the equations to get $0$?
   Is it possible to get this answer from both machines?

   Answer(b):

   He cannot get an output of 0 with Relation A.  He can get an output of 0 by putting a 4 in Function B