1. **State the problem:**
Solve the differential equation $$\left(1-\frac{3}{y}+x\right)\frac{dy}{dx}+y=\frac{3}{x}-1$$ for $y$ as a function of $x$.
2. **Rewrite the equation:**
We want to isolate $\frac{dy}{dx}$:
$$\left(1-\frac{3}{y}+x\right)\frac{dy}{dx} = \frac{3}{x} - 1 - y$$
3. **Express $\frac{dy}{dx}$ explicitly:**
$$\frac{dy}{dx} = \frac{\frac{3}{x} - 1 - y}{1 - \frac{3}{y} + x}$$
4. **Simplify the denominator:**
Rewrite $1 - \frac{3}{y} + x$ as $\frac{y - 3 + xy}{y} = \frac{y(x+1) - 3}{y}$.
5. **Rewrite $\frac{dy}{dx}$ using this:**
$$\frac{dy}{dx} = \frac{\frac{3}{x} - 1 - y}{\frac{y(x+1) - 3}{y}} = \left(\frac{3}{x} - 1 - y\right) \cdot \frac{y}{y(x+1) - 3}$$
6. **Rewrite numerator:**
$$\frac{3}{x} - 1 - y = \frac{3 - x - xy}{x}$$
7. **Substitute back:**
$$\frac{dy}{dx} = \frac{3 - x - xy}{x} \cdot \frac{y}{y(x+1) - 3} = \frac{y(3 - x - xy)}{x(y(x+1) - 3)}$$
8. **Rewrite numerator:**
$$3 - x - xy = 3 - x(1 + y)$$
9. **Rewrite denominator:**
$$y(x+1) - 3 = y(x+1) - 3$$ (already simplified)
10. **Final form:**
$$\frac{dy}{dx} = \frac{y(3 - x(1 + y))}{x(y(x+1) - 3)}$$
11. **Separate variables if possible:**
Rewrite as
$$\frac{y(x+1) - 3}{y(3 - x(1 + y))} dy = \frac{1}{x} dx$$
12. **This is a separable form.**
Integrate both sides:
$$\int \frac{y(x+1) - 3}{y(3 - x(1 + y))} dy = \int \frac{1}{x} dx$$
13. **However, the integral is complicated due to mixed variables.**
This suggests the equation is not separable in the usual way.
14. **Alternative approach:**
Rewrite original equation as
$$\left(1 - \frac{3}{y} + x\right) dy + \left(y - \frac{3}{x} + 1\right) dx = 0$$
15. **Check if exact:**
Let
$$M = 1 - \frac{3}{y} + x, \quad N = y - \frac{3}{x} + 1$$
Compute partial derivatives:
$$\frac{\partial M}{\partial x} = 1, \quad \frac{\partial N}{\partial y} = 1$$
Since $\frac{\partial M}{\partial x} = \frac{\partial N}{\partial y}$, the equation is exact.
16. **Find potential function $\Psi(x,y)$ such that:**
$$\frac{\partial \Psi}{\partial y} = M = 1 - \frac{3}{y} + x$$
Integrate w.r.t. $y$:
$$\Psi = y - 3 \ln|y| + xy + h(x)$$
17. **Differentiate $\Psi$ w.r.t. $x$ and set equal to $N$:**
$$\frac{\partial \Psi}{\partial x} = y + h'(x) = y - \frac{3}{x} + 1$$
Solve for $h'(x)$:
$$h'(x) = - \frac{3}{x} + 1$$
18. **Integrate $h'(x)$:**
$$h(x) = -3 \ln|x| + x + C$$
19. **Write implicit solution:**
$$\Psi(x,y) = y - 3 \ln|y| + xy - 3 \ln|x| + x = C$$
20. **Final answer:**
$$\boxed{y - 3 \ln|y| + xy - 3 \ln|x| + x = C}$$
This implicit solution satisfies the original differential equation.
Differential Equation 3D4558
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