x²-2x-1=0
x2-2x+1-2=0
(x+1)²=2
x+1=±根号2
x1=-1+根号2
x2=-1-根号2
2x^5+4x^4-3x³+3x²-x+4
=2x^5+4x^4+x³-4x³-8x²+11x²-4x+3x+4
=2x³(x+1)²+4x(x+1)²+11x²+3x+4
=4x³+8x+11x²+3x+4
=4x³+11x²+11x+4
=4x³+8x²+3x²+4x+7x+4
=4x(x+1)²+3x²+7x+4
=8x+3x²+7x+4
=3x²+15x+4
=3x²+6x+9x+3+1
=3(x+1)²+9x+1
=6+9x+1
=9x+7
当x1=-1+根号2
原式=-9+9根号2+7=-2+9根号2
当x2=-1-根号2
原式=-9-9根号2+7=-2-9根号2