Logarithm Equation 7845Bf
1. **State the problem:** Solve the equation $$\ln 8 - \ln (-2x) = \ln 13$$ for $x$.
2. **Recall the logarithm property:** The difference of logarithms is the logarithm of the quotient:
$$\ln a - \ln b = \ln \left(\frac{a}{b}\right)$$
3. **Apply the property:**
$$\ln 8 - \ln (-2x) = \ln \left(\frac{8}{-2x}\right) = \ln 13$$
4. **Set the arguments equal:** Since $\ln A = \ln B$ implies $A = B$ (for $A,B>0$), we have:
$$\frac{8}{-2x} = 13$$
5. **Solve for $x$:**
Multiply both sides by $-2x$:
$$8 = 13 \times (-2x)$$
$$8 = -26x$$
Divide both sides by $-26$:
$$x = \frac{8}{-26} = -\frac{4}{13}$$
6. **Check domain restrictions:**
The argument of the logarithm must be positive:
$$-2x > 0 \implies x < 0$$
Our solution $x = -\frac{4}{13}$ satisfies this.
**Final answer:**
$$x = -\frac{4}{13}$$