Diff Eq Simplify
1. **State the problem:** Simplify and solve the differential equation $$3(y + 2) \, dx - x y \, dy = 0$$.
2. **Rewrite the equation:** We have $$3(y + 2) \, dx = x y \, dy$$ or equivalently $$\frac{dx}{dy} = \frac{x y}{3(y + 2)}$$.
3. **Separate variables:** Rewrite as $$\frac{1}{x} \, dx = \frac{y}{3(y + 2)} \, dy$$.
4. **Integrate both sides:**
Left side: $$\int \frac{1}{x} \, dx = \ln|x| + C_1$$
Right side: $$\int \frac{y}{3(y + 2)} \, dy = \frac{1}{3} \int \frac{y}{y + 2} \, dy$$.
5. **Simplify the integrand:**
$$\frac{y}{y + 2} = 1 - \frac{2}{y + 2}$$.
6. **Integrate the right side:**
$$\frac{1}{3} \int \left(1 - \frac{2}{y + 2}\right) dy = \frac{1}{3} \left( y - 2 \ln|y + 2| \right) + C_2$$.
7. **Combine results:**
$$\ln|x| = \frac{y}{3} - \frac{2}{3} \ln|y + 2| + C$$ where $$C = C_2 - C_1$$.
8. **Multiply both sides by 3:**
$$3 \ln|x| = y - 2 \ln|y + 2| + C'$$.
9. **Final implicit solution:**
$$3 \ln|x| = y - 2 \ln|y + 2| + C'$$.
This matches option **b**.
**Answer:** b. $$3 \ln|x| = y - 2 \ln|y + 2| + C$$