To solve for $p$ in terms of $q$ and $r$, we start with the given equation:

$q = -\frac{p}{r}$

Step-by-step solution:

1. Multiply both sides by $r$ to isolate $p$: $q \cdot r = -p$

2. Multiply both sides by $-1$ to solve for $p$: $p = -q \cdot r$

Final answer:

$p = -qr$

Would you like further details on this solution?

Here are five related questions to expand on this:

1. What happens if $r = 0$ in this equation?
2. How would the solution change if $p$ was squared in the original equation?
3. Can you solve for $r$ in terms of $p$ and $q$ from the same equation?
4. What are the implications of the negative sign in the equation?
5. How does this equation relate to direct variation problems?

Tip: When solving for a variable, always check if there are any restrictions (like division by zero) that might affect the solution.