Which of the following is the simplified form of the seventh root of x times the seventh root of x times the seventh root of x ?

When multiplying numbers of the same base , we add the powers.
Example:
2^2 * 2^3 = 2^(2+3) = 2^5

For the givens:
The seventh root of x can be written as x^(1/7)
Now, we need to multiply x^(1/7) by x^(1/7) by x^(1/7)
These numbers have the same base which is "x", therefore, we will just add the power.
This means that:
x^(1/7) * x^(1/7) * x^(1/7) = x^(1/7 + 1/7 + 1/7) = x^(3/7)

Therefore, the correct choice is the first one: x^(3/7)

The percent increase is 25%