已知x-y=3xy,且xy不等于0,则-3x+6xy+3y/(7x-5y)-9xy-(3x-y)

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已知x-y=3xy,且xy不等于0,则-3x+6xy+3y/(7x-5y)-9xy-(3x-y)

已知x-y=3xy,且xy不等于0,则-3x+6xy+3y/(7x-5y)-9xy-(3x-y)
已知x-y=3xy,且xy不等于0,则-3x+6xy+3y/(7x-5y)-9xy-(3x-y)

已知x-y=3xy,且xy不等于0,则-3x+6xy+3y/(7x-5y)-9xy-(3x-y)
因为,x - y = 3xy
所以:-3x+6xy+3y/[(7x-5y)-9xy-(3x-y)]
= [-3(x-y)+6xy]/[(7x-5y) - 9xy - (3x-y)]
= [ -3*3xy + 6xy]/ [ 7x - 5y - 9xy - 3x + y]
= -3xy/ [ 4x -4y -9xy]
= -3xy/[4(x-y)-9xy]
= -3xy/[4*3xy-9xy]
= -1