Question is asking if synthetic division reveals a zero, that means say if you divide x^2-4x+4 by x=2 then we will get last digit as 0 which indicates that x=2 is a solution.
It may happen that solution x=2 repeats more than once.
In that case if you skip division by x=2 then you may get in trouble.
So just to identify any repeated root, we must check that value again as a possible solution.
