待定系数法:
设3x²+2xy-8y²-11x+8y+k=﹙3x-4y-2﹚﹙x+ay+b﹚
=3x²-4xy-2x+3axy-4ay²-2ay+3bx-4by-2b
=3x²+﹙-4+3a﹚xy-4ay²+﹙-2+3b﹚x+﹙2a-4b﹚y-2b,
比较系数得:①-4+3a=2,②-4a=-8,
③-2+3b=-11,④-2a-4b=8,⑤-2b=k,
解得:a=2,b=-3,k=6.
待定系数法:
设3x²+2xy-8y²-11x+8y+k=﹙3x-4y-2﹚﹙x+ay+b﹚
=3x²-4xy-2x+3axy-4ay²-2ay+3bx-4by-2b
=3x²+﹙-4+3a﹚xy-4ay²+﹙-2+3b﹚x+﹙2a-4b﹚y-2b,
比较系数得:①-4+3a=2,②-4a=-8,
③-2+3b=-11,④-2a-4b=8,⑤-2b=k,
解得:a=2,b=-3,k=6.