a x a x a .... (20) times written in exponential form is

The correct answer is:

We will use the rules of indices. If the multiples have same base, their product has sum of their indices.
aⁿa^m = a^{(n + m)}
In this case a is multiplied 20 times.
Here, all the values have same base. And their power is 1.
So, the exponential form will be a²⁰.

For such questions, we should know the rules of indices.