(1a2−ab+b2−b−aa3−b3)÷a4−a2b2−2b4(a6−b6)−(a4+a2b2+b4)\Large{(\frac{1}{a^2-ab+b^2}-\frac{b-a}{a^3-b^3})\div\frac{a^4-a^2b^2-2b^4}{(a^6-b^6)-(a^4+a^2b^2+b^4)}}(a2−ab+b21−a3−b3b−a)÷(a6−b6)−(a4+a2b2+b4)a4−a2b2−2b4
