Answer:
The simplified form is 
The variable n can not be equals to
as for these value denominator equals to zero which becomes an indeterminate form.
Step-by-step explanation:
we have to simplify the rational expression and state the restrictions on the variable.

We can now see that both the numerator and denominator are quadratic trinomials in 
We split the middle terms as follows;




which is the simplified form of given expression.
The variable n can not be equals to
as for these value denominator equals to zero which becomes an indeterminate form.