Assuming that this is just on a 2-D coordinate plane, we must convert the expressions on to a 3-D plane since translation cannot be done on a 2-D plane. This is done by adding a dummy coordinate that does not change. Let us use "1" for this case.
Matrix:
| 0 0 -2 |(x) = (x - 2)
| 0 0 4 |(y) = (y + 4)
| 0 0 1 |(1) = 1
