Look at the denominator .
If n = +1 then .
If n = -1 then .
The denominator cannot equal zero and so n cannot equal +1 or -1.
For the question
i found the answer to be n+2 using long division
in the book the restrictions on the variable says +or - 1
i think it is just +1
could someone explain to me why the book put this (assuming that it is correct of course)