已知3m=4n,则m/m+n+n/m-n-m^2/m^2-n^2=

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已知3m=4n,则m/m+n+n/m-n-m^2/m^2-n^2=已知3m=4n,则m/m+n+n/m-n-m^2/m^2-n^2=已知3m=4n,则m/m+n+n/m-n-m^2/m^2-n^2=m

已知3m=4n,则m/m+n+n/m-n-m^2/m^2-n^2=
已知3m=4n,则m/m+n+n/m-n-m^2/m^2-n^2=

已知3m=4n,则m/m+n+n/m-n-m^2/m^2-n^2=
m/(m+n)+n/(m-n)-m²/(m²-n²)
=m(m-n)/(m+n)(m-n)+n(m+n)/(m-n)(m+n)-m²/(m+n)(m-n)
=(m²+n²-m²)/(m+n)(m-n)
=n²/(m²-n²)
3m=4n m=4n/3
=n²/(16n²/9-n²)
=1/(7/9)
=9/7

9/7不解释。。。。。。。。。。。。。