(where a is a positive number, etc.)
So problem 1:
Note that , so
This can be simplified a little if you like. Note that 15/2 = 7 + 1/2. thus
Note that you can factor a from the LHS:
Now, 27 is not a power of 9. But it is a power of 3:
The bases on each side of the equation are the same, so the exponents must be the same, too.