(3分之1x+y0(3分之x-y)(9分之1x^2+y^2)

问题描述:

(3分之1x+y0(3分之x-y)(9分之1x^2+y^2)
(3分之1x+y)(3分之x-y)(9分之1x^2+y^2)

(3分之1x+y)(3分之x-y)(9分之1x^2+y^2)
=(9分之x²-y²)(9分之1x^2+y^2)
=(x^4-y^4)/81