Hi Connor,

One way to solve this (and I believe to be the easiest to understand and get the right answer) is to instead of diving by -8, multiply by -1/8.  Similar to what you said, it would be like solving a mixed fraction.  Simply multiply by the inverse.  In this case, you have 3/4 * -1/8.  Multiply straight across to get -3/32, and sense this is as simplified as it can be, this is the correct answer.

Hope this helps!

Elijah