∵x2+x-1=0,
∴x2=1-x,x2+x=1,
∵x3-2x+4,
=x(x2-2)+4
=x(1-x-2)+4
=x(-1-x)+4
=-x2-x+4,
=-(x2+x)+4
=3.
故答案为:3.
已知x2+x-1=0,则x3-2x+4的值为_.
已知x2+x-1=0,则x3-2x+4的值为______.
数学人气:345 ℃时间:2019-08-20 13:30:10
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