Ode Solution 838F84
1. **Problem:** Solve the ODE $$(x^2 - 4) y' = -2xy - 6x$$
2. **Rewrite the equation:**
$$y' = \frac{-2xy - 6x}{x^2 - 4}$$
3. **Separate variables or identify the type:** This is a first-order linear ODE in $y$ with respect to $x$.
4. **Rewrite as:**
$$y' + \frac{2x}{x^2 - 4} y = \frac{-6x}{x^2 - 4}$$
5. **Find the integrating factor (IF):**
$$\mu(x) = e^{\int \frac{2x}{x^2 - 4} dx}$$
6. **Calculate the integral in the exponent:**
Let $u = x^2 - 4$, then $du = 2x dx$, so
$$\int \frac{2x}{x^2 - 4} dx = \int \frac{1}{u} du = \ln|u| = \ln|x^2 - 4|$$
7. **Integrating factor:**
$$\mu(x) = e^{\ln|x^2 - 4|} = |x^2 - 4|$$
8. **Multiply both sides by $\mu(x)$:**
$$|x^2 - 4| y' + \frac{2x}{x^2 - 4} |x^2 - 4| y = -6x$$
Simplifies to:
$$(x^2 - 4) y' + 2x y = -6x$$
9. **Recognize left side as derivative:**
$$\frac{d}{dx} \big((x^2 - 4) y\big) = -6x$$
10. **Integrate both sides:**
$$\int \frac{d}{dx} \big((x^2 - 4) y\big) dx = \int -6x dx$$
$$ (x^2 - 4) y = -3x^2 + C$$
11. **Solve for $y$:**
$$y = \frac{-3x^2 + C}{x^2 - 4}$$
**Final answer:**
$$\boxed{y = \frac{C - 3x^2}{x^2 - 4}}$$
This completes the solution for the first ODE.