What is the value of 12^c^3

for those of you confused by this its a C in the middle with a power of three to the bottom left and a power of 12 on the top right.

How would I write (Sqrt)6*36/6^-1 as a single fraction?

And finally, in the expansion of (2x-1)^30

What is the co efficient of x^2. I know you use pascals triangle but im confused with the theory of how to do it

Thanks a lot