已知x²+4x-1=0,求2x⁴+8x³-4x²-8x+1的值.
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已知x²+4x-1=0,求2x⁴+8x³-4x²-8x+1的值.
已知x²+4x-1=0,求2x⁴+8x³-4x²-8x+1的值.
已知x²+4x-1=0,求2x⁴+8x³-4x²-8x+1的值.
2x⁴+8x³-4x²-8x+1
=2x(x²+4x-1)-(2x²+8x-1)
=2x²(x²+4x-1)-(2x²+8x-2)-1
=2x²(x²+4x-1)-2(x²+4x-1)-1
=-1
2x⁴+8x³-4x²-8x+1=2x²﹙x²+4x-1﹚-﹙2x²+8x-1﹚=0-2﹙x²+4x-1﹚=0-0=0