Let's write out the problem and see if there is anything we can simplify.

The numerator 6 and the denominator 8 can be simplified to 3 and 4 by taking out a 2.
The numerator 3 and the denominator 9 can be simplified to 1 and 3 by taking out a 3.
Now our expression is

.
The fraction 3/3 reduces to 1 since the denominator and numerator are the same and not 0, making our answer
1/4.