﹙1﹚﹙4a²-8ab﹚+2﹙a²b-2ab﹚
=4a²-8ab+2a²b-4ab
=4a²-12ab+2a²b.
﹙2﹚﹙m²-3m+4﹚-3﹙2m-m²﹚
=m²-3m+4-6m+3m²
=4m²-9m+4