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已知x2+x-1=0,求x³+2x²+2006
人气:417 ℃ 时间:2020-06-28 16:30:02
解答
答:
x^2+x-1=0
x^2=1-x
x^3+2x^2+2006
=(1-x)x+2x^2+2006
=x+x^2+2006
=1+2006
=2007
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