What is the answer of a 0a?

The expression (0^a) (zero raised to the power of a) depends on the value of (a). If (a) is a positive number, (0^a) equals 0. If (a) is zero, (0^0) is often considered indeterminate or defined as 1 in some contexts. If (a) is negative, (0^a) is undefined since it involves division by zero.