Answer:
She made a mistake in step 3
She simplified the 3^-8 incorrectly
she should've added them
the answer is 3^24 if you need that
Explanation:
using the following rule
![b/x^(-n)=bx^n](https://img.qammunity.org/2022/formulas/mathematics/college/92yokd7rnuttz3yh0072hledlaai8hppe3.png)
we can see that she made a made a mistake in step 3 when simplifying
she should've added 3^8 to 3^16 rather than subtracting them