若x^2n=7 则(x^3n)^2 =_____

问题描述:

若x^2n=7 则(x^3n)^2 =_____

答:若x^2n=7 则(x^3n)^2 =_343
解 (x^3n)^2=x^(6n)=(x^2n)^3=7^3=343