(x^3+2x-1)+(x^2-x-1)

(x^3+2x-1)+(x^2-x-1)
=x^3+2x-1+x^2-x-1
=x^3+x^2+2x-x-1-1
=x^3+x^2+x-2



所以個answer系 x^3+x^2+x-1

(x^3+2x-1)+(x^2-x-1)
=x^3+2x-1+x^2-x-1
=x^3+x^2+2x-x-1-1
=x^3+x^2+x-2
=x^3+(x-2)(x+1)
只可以簡化到e到..
之後係唔可以再簡化...