Find the hcf of 12araisedto Power3b,9 ab, 15a'2'b'3',24ab'2'x
No idea. You have a mish-mash of notations. Try using the most common online one: ^ for power, as in
12araisedto Power3b = (12a)^(3b)
and so on for your others.
12araisedto Power3b = (12a)^(3b)
and so on for your others.