Answer: n = 17
Step-by-step explanation: We can simplify 9 x 3^15 by first writing 9 as 3^2. Then we can use the rule that says when you multiply two numbers with the same base, you can add their exponents. So:
9 x 3^15 = 3^2 x 3^15 = 3^(2+15) = 3^17
Therefore, n = 17.