#1**+2 **

None of your choices provide the correct solution to what you have written!

3^{n+2} + 3^{n+3} - 3^{n+1} → 3^{n+1}(3^{1} + 3^{2} - 3^{0}) → 3^{n+1}(3 + 9 - 1) → 11*3^{n+1}

I think you must have meant 3^{n+2} / (3^{n+3} - 3^{n+1}) → 3^{1} / (3^{2} - 3^{0}) → 3 / (9 - 1) → 3/8 (where 3^{n+1} has been factored out of the terms in both numerator and denominator).

Alan Oct 27, 2018