# exponentials

• September 20th 2009, 06:30 AM
pop_91
exponentials
i need to solve this giving and exact solution...

2e^(x) + 3e^(-x)=7

thanks
• September 20th 2009, 06:41 AM
e^(i*pi)
Quote:

Originally Posted by pop_91
i need to solve this giving and exact solution...

2e^(x) + 3e^(-x)=7

thanks

Let $e^x = u
$

$2u + \frac{3}{u} = 7$
• September 20th 2009, 06:42 AM
Prove It
Quote:

Originally Posted by e^(i*pi)
Let $e^x = u
$

$2u + \frac{3}{u} = 7$

Further hint: Multiply both sides of the equation by $u$.
• September 20th 2009, 07:41 AM
pop_91
major thanks guys