a²+3a+1=0a²+3a=-1;a²=-3a-1;a²+5=-3a+4;a²-1=-3a-2,3a³+﹙a²+5﹚﹙a²-1﹚-a﹙5a+6)=3a³+﹙-3a+4﹚﹙-3a-2﹚-5a²-6a=3a³+9a²+6a-12a-8-5a²-6a=3a...