作业帮***若3x²-x=1,则9x^4+12x³-2x²-7x+2008的值等于多少?
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***若3x²-x=1,则9x^4+12x³-2x²-7x+2008的值等于多少?
***若3x²-x=1,则9x^4+12x³-2x²-7x+2008的值等于多少?
***若3x²-x=1,则9x^4+12x³-2x²-7x+2008的值等于多少?
3x²-x=1 3x²-x-1=0
9x⁴+12x³-2x²-7x+2008
=9x⁴-3x³-3x²+15x³-5x²-5x+6x²-2x-2+2010
=3x²(x²-x-1)+5x(3x²-x-1)+2(3x²-x-1)+2010
=0+0+0+2010
=2010
若3x²-x=1,
,则9x^4+12x³-2x²-7x+2008
=3x²(3x²-x)+3x³+12x³-2x²-7x+2008
=3x²+15x³-2x²-7x+2008
=15x³+x²-7x+2008
=5x(3x²-x)+6x²-7x+2008
=5x+6x²-7x+2008
=6x²-2x+2008
=2(3x²-x)+2008
=2010