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问题: X^4-X^3+6X^2-X+15

X^4-X^3+6X^2-X+15的全过程和方法

解答:

x^4-x^3+6x^2-x+15
=x^4-x^3+8x^2-2x^2-x+16-1
=x^4+16+8x^2-x^3-2x^2-x-1
=(x^2+4)^2-(x^3+2x^2+x+1)
=(x^2+4)^2-[x(x^2+2x+1)+1]
=(x^2+4)^2-[x(x+1)^2+1]
=(x^2+4)^2-x(x+1)^2-1
=(x^2+4-x^2-1)(x^2+4+x^2+1)-1
=3(2x^2+5)-1
=6x^2+15-1
=6x^2+14