## Precalculus (6th Edition) Blitzer

$x\approx 1.43$
$e^{12-5x}-7=123\qquad$ ... add 7 to both sides $e^{12-5x}=130\qquad$ ... apply $\ln$( ) to both sides $\ln e^{12-5x}=\ln 130\qquad$ ... apply basic property, $\log_{b}b^{x}=x$ $12-5x= \ln 130\qquad$ ... add $5x-\ln 130$ to both sides $12-\ln 130=5x\qquad$...divide both sides with $5$ $x=\displaystyle \frac{12-\ln 130}{5}\qquad$... round to two decimal places $x\approx 1.43$