已知X=2.5,Y=1,求分式-X²+8XY-15Y²/X²-3XY-10Y²的值谢谢

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已知X=2.5,Y=1,求分式-X²+8XY-15Y²/X²-3XY-10Y²的值
谢谢

原式=-(x-3y)(x-5y)/(x-5y)(x+2y)=-(x-3y)/(x+2y)=-1/9

-(X-3Y)(X-5Y)/(X-5Y)(X+2Y)
=-X+3Y/X+2Y(X不等於5Y)
=0.5/4.5
=1/9