1已知a^2n=4,求(2a^3n)^2-(6a^4n+1)*(-5a^4n-1)

(2a^3n)^2-(6a^4n+1)*(-5a^4n-1)
=2^2*a^6n-6*(-5)*a^4n+1+4n-1)
=4*(a^2n)^3+30*a^(8n)
=4*(a^2n)^3+30*(a^2n)^4
=4*4^3+30*4^4
=256+30*256
=7936
-(1/2)ab(a+ba^3-b^2a^5)
=-(1/2)(a^2b+a^4b^2-a^6b^3)
=-1/2[ba^2+(ba^2)^2-(ba^2)^3]
=-1/2*(2+2^2-2^3)
=-1/2*(2+4-8)
=-1/2*(-2)
=1

a^n=2,
那么(2a^3n)^2-(6a^4n+1)*(-5a^4n-1)
=（2*2^3）^2-（6*2^4+1）*（-5*2^4-1）
=64+97*81
=7921

1，A=2 N=1 剩下的自己求
2、a=1 b=2