1. **Restate step 7:** We have the equation from step 6: $$-96a - 1392d = 0$$ 2. **Goal:** Simplify this equation by dividing every term by the common factor to make it easier to work with. 3. **Find the common factor:** Both $-96$ and $-1392$ are divisible by $-96$. 4. **Divide each term by $-96$:** $$\frac{-96a}{-96} + \frac{-1392d}{-96} = \frac{0}{-96}$$ 5. **Simplify each fraction:** $$a + 14.5d = 0$$ 6. **Explanation of the second 96:** The second 96 in the division is the denominator for the term $-1392d$. Dividing $-1392d$ by $-96$ gives $14.5d$ because $1392 \div 96 = 14.5$. 7. **Summary:** Dividing the entire equation by $-96$ cancels the $-96$ in the first term and simplifies the second term to $14.5d$, making the equation easier to solve.