You really should learn to type in LaTex. I can barely read your post.
You mean this?1. 12u cubed/7v to the fifth * 14v squared/3u =
8 u squared/ v cubed
If so, then
You mean this?2. 9x * 4/x =
If so, and assuming that x isn't 0, then 36 is right.
I'm not even touching this one.3. x squared -3x +2/x squared -4x +4 divided by x squared -2x +1/ 3x squared -12 =
You mean this?4. 15 divided by 5x/x+1 =
3(x+1) / x
You mean this?5. 6x/x-2 divided by 3x =