1-a^3-b^3/(a^2-b^2)(a-b)

Question

1-a^3-b^3/(a^2-b^2)(a-b)

Answer 1

(-a^3-b^3)/((a^2-b^2)(a+b))=-((a+b)(a^2-ab+b^2))/(a^2-b^2)(a+b)=-(a^2-2ab+b^2/(a^2-b^2=
=-(9-12+6)/(9-16)=13/7