8b^3-a^3+a-2b _________________ 1- (a+b) ^2-3b^2

8b^3-a^3+a-2b (2b-a) (4b^2+2ab+a^2) — (2b-a) _________________=__________________________=1- (a+b) ^2-3b^2 1-a^2-b^2-3b^2=(2b-a) (4b^2+2ab+a^2-1) ___________________________=- (2b-a)=a-2b — (4b^2+2ab+a^2-1)