# Isolating x

1. Mar 24, 2004

### mwall

I am working on a problem relating to rate of reaction. I am not sure how to isolate the x in the following equation.

e^-45/(8.31)(x)
e^-45/(8.31)(353)

mwall

2. Mar 24, 2004

### mwall

Sorry, I forgot the rest of the equation.

.072 = e^-(45/8.31*x)
.002 e^-(45/8.31*352)

mwall

3. Mar 24, 2004

### uart

Whenever you're not sure how to proceed with rearranging an expression like that one the first thing you should do is to "fold" the constants together. If you do so then it is simply expressed as,

$$e^{ax} = b$$.

So obviously you just need to take logs of both sides to get,

$$x = \frac{\log(b)}{a}$$

Last edited: Mar 24, 2004
4. Mar 24, 2004

### da_willem

This can be done by remembering $$e^a / e^b = e^{a-b}$$

5. Mar 24, 2004