# Math Help - solve for x

1. ## solve for x

I am trying to solve this equation and find x
The equation is:
e^(-2x)-7e^(-x)=8
I tried multiplying everything by e^(x), but that didnt seem to help
I got e^(x)-7=8e^(x)
That can be simplified as -7 = 7e^(x)
at this point there is not value for x that would work.
Help??
Thanks once again.

2. Note $e^{-x}=y$ and you get $y^2-7y=8$