Answer:
(3-x) is the other factor.
Step-by-step explanation:
The given function is :

One of the factor is (x-4)
We need to find the other factor.
It can be solved as follows :

So, the other factor is (3-x).
The first expression goes into m - 1
the second expression is m - 2 / m
and the last expression goes m - 2 / m - 1