I would personally use natural logs to solve this. You can solve any problem like this if you know how how to use natural logs. So lets start
4^m=1/32
First I apply a natural log to both sides of the equation
ln(4^m)=ln(1/32)
Because of the properties of logarithms, I can take out that m on the left and have it multiply. Like this
m*ln(4)=ln(1/32)
Now from here the math turns to more basic algebra. This is your answer to m
m=ln(1/32)/ln(4)
That is the answer in its unsimplified form. However, if you look closely, this answer can be decomposed into something simpler. Again we need to use the properties of logarithms to decompose this to something simpler.
m=ln(1/32)/ln(4)
Below I use the properties of logs over and over again
m=(ln(1)-ln(32))/ln(4)
m=-ln(2^5)/ln(2^2)
m=(5*-ln(2))/(2*ln(2))
cancel the ln(2)
m=-5/2
I'm hoping you could follow that. If you couldn't then I highly recommend you check out pages like this to figure out how logs work-
http://uncw.edu/courses/mat111hb/EandL/logprop/logprop.html
Anyway. Sometimes you can simplify but other times you really can't. It all depends on what equation you're given to solve.
I hope this information helped you out.