设m等于1/5n求 2n/(m+2n)+m/(2n-m)+4mn/(4n²-m²)
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设m等于1/5n求 2n/(m+2n)+m/(2n-m)+4mn/(4n²-m²)
先化简 再求值
先化简 再求值
原式
=2n/(m+2n)-m/(m-2n)-4mn/(m²-4n²)
=2n/(m+2n)-m/(m-2n)-4mn/(m²-4n²)
=[2n(m-2n)-m(m+2n)-4mn]/(m²-4n²)
=(2mn-4n²-m²-2mn-4mn)/(m²-4n²)
=(-4n²-m²-4mn)/(m²-4n²)
=-(m+2n)²/[(m+2n)(m-2n)]
=-(m+2n)/(m-2n)
m=1/5n,则n=5m,于是
原式
=-(m+10m)/(m-10m)
=-11m/(-9m)
=11/9
=2n/(m+2n)-m/(m-2n)-4mn/(m²-4n²)
=2n/(m+2n)-m/(m-2n)-4mn/(m²-4n²)
=[2n(m-2n)-m(m+2n)-4mn]/(m²-4n²)
=(2mn-4n²-m²-2mn-4mn)/(m²-4n²)
=(-4n²-m²-4mn)/(m²-4n²)
=-(m+2n)²/[(m+2n)(m-2n)]
=-(m+2n)/(m-2n)
m=1/5n,则n=5m,于是
原式
=-(m+10m)/(m-10m)
=-11m/(-9m)
=11/9
设m等于1/5n求 2n/(m+2n)+m/(2n-m)+4mn/(4n²-m²)
设m=1/5n 设m等于1/5n求 2n/(m+2n)+m/(2n-m)+4mn/(4n²-m²)
已知:m*m=n+2,n*n=m+2.求m*m*m-2mn+n*n*n(m不等于n).
【(m+n)(m-n)-(m-n²)+2n(m-n)】÷4n
[(m+n)(m-n)-(m-n)²+2n(m-n)]÷4n
已知m²=n+4,n²=m+4(m≠n),求m³-2mn+n³的值
已知m/n=5、,求(m/(m+n))+(m/(m-n))-(n^2/(m^3-n^2))
已知m,n满足4m²+n²=5,mn=-1,求4m²-4mn+n²/2m+n除以
1+n-m÷m²-n² --- ---- m+2n m²+4mn+4n²
1+n-m/m+2n÷m²-n²/m²+4mn+4n²=
化简m/(m+n)²+n/m²-n²-2n²/(m+n)(m²-n
{(m+n)²-4mn}{(m-n)²+4mn}+2(mn)²等于多少?