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已知m05-5m-1=0,则2m05-5m+m²分之一等于多少
人气:355 ℃ 时间:2019-10-09 12:28:41
解答
m^2-5m-1=0
m^2-5m=1
m^2-5m-1=0
m-5-1/m=0
m-1/m=5
m^2+1/m^2
=(m-1/m)^2+2
=5^2+2
=25+2
=27
2m^2-5m+1/m^2
=m^2-5m+m^2+1/m^2
=1+27
=28
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