1. **State the problem:** Solve the equation $\lg(x^2) - \lg^2(-x) = 3$ for $x$.
2. **Recall the definitions and domain restrictions:**
- $\lg$ denotes the base-10 logarithm.
- The argument of a logarithm must be positive.
- So, for $\lg(x^2)$, since $x^2 \geq 0$, the argument is positive for all $x \neq 0$.
- For $\lg(-x)$, the argument $-x$ must be positive, so $-x > 0 \Rightarrow x < 0$.
3. **Rewrite the equation:**
$$\lg(x^2) - \left(\lg(-x)\right)^2 = 3$$
4. **Use logarithm properties:**
Since $\lg(x^2) = 2\lg|x|$, and for $x<0$, $|x| = -x$, so:
$$2\lg(-x) - \left(\lg(-x)\right)^2 = 3$$
5. **Let $y = \lg(-x)$, then the equation becomes:**
$$2y - y^2 = 3$$
6. **Rewrite as a quadratic equation:**
$$-y^2 + 2y - 3 = 0$$
Multiply both sides by $-1$:
$$y^2 - 2y + 3 = 0$$
7. **Solve the quadratic equation:**
The discriminant is:
$$\Delta = (-2)^2 - 4 \times 1 \times 3 = 4 - 12 = -8$$
Since $\Delta < 0$, there are no real solutions for $y$.
8. **Conclusion:**
No real $y$ satisfies the equation, so no real $x$ satisfies the original equation under the domain restrictions.
**Final answer:** No real solution for $x$.
Logarithmic Equation 6906Be
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