已知m^2=2n+5,n^2=2m+5,且m不等于n,求m^3-4mn+n^3的值

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已知m^2=2n+5,n^2=2m+5,且m不等于n,求m^3-4mn+n^3的值
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已知m^2=2n+5,n^2=2m+5,且m不等于n,求m^3-4mn+n^3的值
已知m^2=2n+5,n^2=2m+5,且m不等于n,求m^3-4mn+n^3的值

已知m^2=2n+5,n^2=2m+5,且m不等于n,求m^3-4mn+n^3的值
m^3-4mn+n^3=m(2n+5)-4mn+n(2m+5)
=5m+5n
m^2=2n+5,n^2=2m+5两个相减得
m^2-n^2=2(m-n)
因为m不等于n
m+n=2
所以上边得是10