已知a^2n=2,求（2a^3n)^2-6a^2n+1乘(-5a^2n-1)的值
问题描述：
已知a^2n=2,求（2a^3n)^2-6a^2n+1乘(-5a^2n-1)的值
答
(2a^3n)^2-6a^(2n+1)*(-5a^(2n-1))
=4a^6n-6*(-5)*a^(2n+1+2n-1)
=4(a^2n)^3+30(a^2n)^2
=4*2^3+30*2^2
=32+120
=152