-(b-2)(b+2)-2(b+4)(b+2)=
-(b²-4)-2(b²+2b+4b+8)=-(b²-4)-2(b²+6b+8)=-b²+4-2b²-12b-16=-3b²-12b-12
#2
(a-3)(a+1)-(a+6)³=a²+a-3a-3-(a+6)(a+6)(a+6)
a²-2a-3-(a²+6a+6a+36)(a+6)=
a²-2a-3-(a³+6a²+6a²+36a+6a²+36a+36a+216)=
a²-2a-3-a³-18a²-108a-216=-a³-17a²-110a-219