# If #5^-x = 1/3#, then what is the value of #25^x#?

##### 2 Answers

Nov 26, 2017

#### Explanation:

First solve for x

Therefore

So the only part I want to emphasize is the log operation. Log is a nice way to change multiplication and division into addition and subtraction. Another benefit is that any power becomes a multiple. Uaing it allowed me to bring x down and then solve more simply.

Nov 27, 2017

#### Explanation:

Alternate way of doing it.

We know that

We know from the first equation that

This means that

#(5^x)^2 = 3^2 = 9#

Hopefully this helps!