已知:ab=-1 a+b=2,则式子(b/a)+(a/b)=___

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已知:ab=-1a+b=2,则式子(b/a)+(a/b)=___已知:ab=-1a+b=2,则式子(b/a)+(a/b)=___已知:ab=-1a+b=2,则式子(b/a)+(a/b)=___(b/a

已知:ab=-1 a+b=2,则式子(b/a)+(a/b)=___
已知:ab=-1 a+b=2,则式子(b/a)+(a/b)=___

已知:ab=-1 a+b=2,则式子(b/a)+(a/b)=___
(b/a)+(a/b)
=b²/(ab)+a²/(ab)
=(b²+a²)/(ab)
=(a²+b²+2ab-2ab)/(ab)
=[(a+b)²-2ab]/(ab)
=[2²-2*(-1)]/(-1)
=(4+2)/(-1)
=-6

=(a²+b²)/ab=[(a+b)²-2ab]/ab=(4+2)/(-1)=-6

-6,(b/a)+(a/b)=(b平方+a平方)/ab={(a+b)平方-2ab}/ab=[4-(-2)]/-1=-6