This x is called the n-th root of a, where n >；; 1, and n ∈ n There is a requirement for the parity of n. When n is odd, then:

The exponential power of the fraction also needs to be remembered. When calculating some fractions by substitution, we should know the exponential power of fractions and related operational properties. Operational properties of fractional powers;

For the calculation and simplification of roots, it is necessary to pay attention to whether n is positive odd or positive even, because the parity of n determines the sign of numbers. From the operation of fractional exponential power, it should be noted that: 1) the same base power is multiplied, and the indexes can be added. 2) The final result of the operation cannot contain both radical and fractional exponent, nor can it contain both denominator and negative exponent. 3) When the radix is negative, it is necessary to determine the symbol first, then change the negative radix into a positive radix, and then calculate to avoid losing the symbol in the final result.