2016-04-09 09:04发布
l x+1 3x x-2 x-1 l
=(x+1)*(x-1)-3x*(x-2)
=x²-1-3x²+6x
=-2x²+6x-1
=-2(x²-3x)-1
因为x²-3x+1=0
所以x²-3x=-1
所以:原式=-2*(-1)-1
=2-1
=1
|x+1 3x x-2 x-1|=(x+1)(x-1)-(3x)(x-2)=x²-1-(3x²-6x)=-2x²+6x-1
-2x²+6x-1=-2(x²-3x+1)+1,∵x²-3x+1=0
∴|x+1 3x x-2 x-1|=1
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l x+1 3x x-2 x-1 l
=(x+1)*(x-1)-3x*(x-2)
=x²-1-3x²+6x
=-2x²+6x-1
=-2(x²-3x)-1
因为x²-3x+1=0
所以x²-3x=-1
所以:原式=-2*(-1)-1
=2-1
=1
|x+1 3x x-2 x-1|=(x+1)(x-1)-(3x)(x-2)=x²-1-(3x²-6x)=-2x²+6x-1
-2x²+6x-1=-2(x²-3x+1)+1,∵x²-3x+1=0
∴|x+1 3x x-2 x-1|=1
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