(b/a^3+ab + 2/a+b) +a/b^2+ab)

Question

(b/a^3+ab + 2/a+b) +a/b^2+ab)

Answer 1

a^3-ab-a^2b+a^2=a^2(a-b)+a(a-b)=(a-b)(a^2+a)=a(a-b)(a+1)