loga(x^2+4)+loga(y^2+1)=loga5+loga(2xy-1)(a>0,a≠1)求log8(y/x)

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loga(x^2+4)+loga(y^2+1)=loga5+loga(2xy-1)(a>0,a≠1)求log8(y/x)
loga(x^2+4)+loga(y^2+1)=loga5+loga(2xy-1)(a>0,a≠1)求log8(y/x)

loga(x^2+4)+loga(y^2+1)=loga5+loga(2xy-1)(a>0,a≠1)求log8(y/x)
依题意可得:(x²+4)(y²+1) = 5(2xy-1) ,
整理得:(xy-3)²+(x-2y)² = 0 ;
因为,(xy-3)² ≥ 0 ,(x-2y)² ≥ 0 ,
所以,xy-3 = 0 ,x-2y = 0 ;
可得:x = 2y ,
即有:y/x = 1/2 ,
所以,log8(y/x) = log8(1/2) = -1/3 .

-1/3