How do you solve #5^-x = 3#?

1 Answer
Jun 3, 2016

Using the log.

Explanation:

To solve the equations where the #x# is in the exponent, the trick is to do the logarithms.

#5^(-x)=3#

#log(5^(-x))=log(3)#

we then apply the property of the logarithm where the exponent in the log goes in front multiplying.

#-xlog(5)=log(3)#

#x=-log(3)/log(5)\approx-0.68#.