# How do you solve 2e^(2x)-9e^x -5=0?

May 10, 2016

$x = \ln 5.$

#### Explanation:

This is a quadratic in ${e}^{x}$. The roots are ${e}^{x} = \frac{9 \pm \sqrt{121}}{4}$

$= 5 , \frac{1}{2}$.

As ${e}^{x} \ge 0$, negative root is inadmissible..

Inverting, x= ln 5. .