^

are you missing an operator here?
>> 9^(n1).(2)^(n+1) + (2)^(n1).9^(n+1)  2(9^n (2)^n)
>> is it possible to simplify this any further?
You can do some simplifying
Rules:
a^(b+c) = a^b a^c
a^(bc) = a^b a^(c) = a^b / a^c
For example, 9^(n+1) = 9^n * 9 and (2)^(n1) = (2)^n / (2)^(1)
You should end up with some common factors.