You answered your own question?
Power
103 x
An exponent.
You can but it has no particular significance.
No.
You answered your own question?
negative 8 would be the base and the 15 would be the exponent
103 x
5de
Power
Most likely it is a logarithm.
In the expression 45 the 4 is the base and the 5 is the exponent.
Then, if the exponent is a positive integer, the value is 1 multiplied by the base repeatedly, exponent times. If the exponent is a negative integer then it is the reciprocal of the above value.In either case, it is NOT the base multiplied by itself an exponent number of times.
An exponent.
You can but it has no particular significance.
7n^5