We have the following fractional expression:
12
-------- is the same as
12^3
12^1
-------
12^3
We want to simplify this expression. To do so, we need the formula for exponents as follows:
x^a / x^b = x^(a-b).
In this particular problem we have
12^1 / 12^3, and know by this formula that the correct result is 12^(1-3), or 12^(-2), which is equivalent to 1 / 144.