Question

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

Answer 1

`x=ln 5.`

Explanation:

This is a quadratic in `e^x`. The roots are `e^x=(9+-sqrt(121))/4`

`=5, 1/2`.

As `e^x>=0`, negative root is inadmissible..

Inverting, x= ln 5. .