若a为正整数,且x^2n=7,求(x^3n)^2-(x^2)^2n的值

问题描述:

若a为正整数,且x^2n=7,求(x^3n)^2-(x^2)^2n的值

(x^3n)^2-(x^2)^2n
=x^6n-x^4n
=(x^2n)^3-(x^2n)^2
=7^3-7^2
=294