(x+3y)(x-3y)(x^2+9y^2) 和 (-3)^2n+1+3(-3)^2n

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(x+3y)(x-3y)(x^2+9y^2) 和 (-3)^2n+1+3(-3)^2n
(x+3y)(x-3y)(x^2+9y^2) 和 (-3)^2n+1+3(-3)^2n

(x+3y)(x-3y)(x^2+9y^2) 和 (-3)^2n+1+3(-3)^2n
1(x+3y)(x-3y)(x^2+9y^2) =(x^2-9y^2) (x^2+9y^2) =(x^4-81y^4)
(-3)^2n+1+3(-3)^2n
2是不是)(-3)^(2n+1)+3(-3)^2n=(-3)^(2n+1)-(-3)(-3)^2n=
(-3)^(2n+1)-(-3)^(2n+1)=0

(x+3y)(x-3y)(x^2+9y^2)
=(x²-9y²)(x²+9y²)
=x^4-81y^4

(-3)^2n+1+3(-3)^2n
=-3^(2n+1)+3×3^(2n)
=-3^(2n+1)+3^(2n+1)
=0

化简吗?
x^4-81y^4
4*9^n+1