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回答时间:2025-01-22 22:52
解法1: 3x²-x=1,则:
6x³+7x²-5x+2006
=2x(3x²-x)+3(3x²-x)-2x+2006
=2x*1+3*1-2x+2006
=2x+3-2x+2006
=2009
解法2: 3x²-x=1,则3x²-x-1=0.
6x³+7x²-5x+2006
=2x(3x²-x-1)+3(3x²-x-1)+2009
=2x*0+3*0+2009
=2009
解法3: 3x²-x=1,则6x³-2x²=2x.
6x³+7x²-5x+2006
(6x³-2x²)+3(3x²-x)-2x+2006
=2x+3*1-2x+2006
=2x+3-2x+2006
=2009
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