-(b-2)(3-4b) (b+2)(3-2b) (b-4)^2
-(b-2)(3-4b)=-(3b-4b²-6+8b)=-3b+4b²+6-8b=4b²-11b+6 (b+2)(3-2b)=3b-4b²+6-4b=-4b²-b+6 (b-4)²=b²-8b+16