Needing help with these problems lost, subtract. simplify if possible 3/x-9 - 3/ 9-x, divide and simpliify 6/t divide 18/t, add. simplify is possible 5/z-8 + 12/(z-18)^2

I am not sure if I have the problems right. For what I think is the first question:

3/(x-9) - 3/(9-x)

However, (9-x) = -1(x-9)

Therefore 3/(x-9) - 3/(9-x) = 3/(x-9) + 3/(x-9) =
6/(x-9)

I hope this helps. If not, please repost, clarifying your questions. Thanks for asking.