Question

化简：（a-1)(a+1)(a2+1) (1/3+a)(1/3-a)(1/9+a2) (4+y2)(2+y)(2-y)

Answer 1

（a-1)(a+1)(a^2+1)

=(a^2-1)(a^2+1)

=a^4-1

(1/3+a)(1/3-a)(1/9+a^2)

=(1/9-a^2)(1/9+a^2)

=1/81-a^4

(4+y^2)(2+y)(2-y)

=(4+y^2)(4-y^2)

=16-y^4

(1/9y^2+x^2)(1/3y-x)(1/3y+x)

(1/9y^2+x^2)(1/9y^2-x^2)

=1/81y^4-x^4