Solution -:

-3x7x7x7x7x7x7

We have,,

- exponent and shortcut to express a multiplication of number by itself several times explain us how many time we should multiply the number by itself this process of using exponent is called raising to a power where the exponent is the power.
Law of exponent -:
- a ⁰ = 1
- a ^ m × a ^ n
- (a^m)^n
- a^m × b^ m
As like example→ 2⁴
here 2 is base and 4 is power , index or exponent. and 2⁴ is known as Exponential form.