Hi Seth,
Sometimes it's difficult to understand what's in the denominator. It's helpful to use additional parentheses or brackets. Having said this, this is how I'm interpreting your post.
6st-2
------- with the entire expression raised to the -4
3s2t-5
This is equivalent to
3s2t-5
------- with the entire expression raised to the +4
6st-2
Now that +4 exponent can be distributed to each factor in the expression, giving us
34s8t-20
---------
64s4t-8
Now let's move the terms with the negative exponents so that they are positive
34s8t8
--------
64s4t20
And simplify the variables
34 s4
-------
64 t12
Finally, 6 = (3)(2) so 64 = (3)4(2)4, making the expression
34 s4
---------
3424 t12
---------
3424 t12
which reduces to
s4
-------- and further reduces to
24 t12
s4
-------
16t12