1. The problem asks to rewrite the expression $9 \cdot 9^2$ in the form $9^n$. 2. Recall the exponent property for multiplication with the same base: $$a^m \cdot a^n = a^{m+n}$$ where $a$ is the base and $m,n$ are exponents. 3. In the expression $9 \cdot 9^2$, we can rewrite $9$ as $9^1$ because any number to the power of 1 is itself. 4. So, $$9 \cdot 9^2 = 9^1 \cdot 9^2$$ 5. Applying the exponent property: $$9^1 \cdot 9^2 = 9^{1+2} = 9^3$$ 6. Therefore, the expression $9 \cdot 9^2$ rewritten in the form $9^n$ is $$9^3$$. Final answer: $n = 3$.