Solve Nonlinear
1. **State the problem:** We are given the equation $$xy^3 - 4x^2 = 10y^2$$ and we want to analyze or possibly solve it for one variable in terms of the other.
2. **Rewrite the equation:** $$xy^3 - 4x^2 = 10y^2$$
3. **Attempt to solve for $x$ in terms of $y$: Rewrite terms involving $x$ on one side:**
$$xy^3 = 10y^2 + 4x^2$$
4. This is a nonlinear equation in terms of $x$ and $y$. Try expressing $x$ explicitly by isolating terms.
5. Rearrange to isolate $x$ terms on one side:
$$xy^3 - 4x^2 = 10y^2$$
$$x y^3 = 10 y^2 + 4 x^2$$
6. Let us move all terms to one side:
$$0 = 10 y^2 + 4 x^2 - x y^3$$
7. Treating this as a quadratic in $x$:
$$4 x^2 - y^3 x + 10 y^2 = 0$$
8. Use the quadratic formula for $x$:
$$x = \frac{y^3 \pm \sqrt{(y^3)^2 - 4 \cdot 4 \cdot 10 y^2}}{2 \cdot 4}$$
9. Simplify under the square root:
$$x = \frac{y^3 \pm \sqrt{y^6 - 160 y^2}}{8}$$
10. Factor $y^2$ inside the root:
$$x = \frac{y^3 \pm y \sqrt{y^4 - 160}}{8}$$
11. **Final expression:**
$$x = \frac{y^3 \pm y \sqrt{y^4 - 160}}{8}$$
This shows how $x$ is related to $y$ with possible restrictions where the discriminant is non-negative:
$$y^4 - 160 \geq 0 \implies y^4 \geq 160$$
So solutions are valid where $|y| \geq \sqrt[4]{160}$.
**Summary:** We solved the equation for $x$ in terms of $y$ and found the domain constraints for real solutions.