## Precalculus (6th Edition) Blitzer

Use the quotient rule $\log_b{\dfrac{p}{q}}=\log_b{p} - \log_b{q}$ with $p=x-4$ and $q=x+1$ to obtain $\ln {\dfrac{x-4}{x+1}}=\ln 6$ Simplify to obtain: $\dfrac{x-4}{x+1}=6$ $x-4 = 6x+6 \implies x=-2$ But we just reject this solution because we can not take the log of a negative number.