已知-3/7a的(平方+m)b(2n-1)是四次单项式,求m²n-m²-m(4n+mn)-(-2n)²的值
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已知-3/7a的(平方+m)b(2n-1)是四次单项式,求m²n-m²-m(4n+mn)-(-2n)²的值
已知-3/7a的(平方+m)b(2n-1)是四次单项式,求m²n-m²-m(4n+mn)-(-2n)²的值
已知-3/7a的(平方+m)b(2n-1)是四次单项式,求m²n-m²-m(4n+mn)-(-2n)²的值
∵-3/7a^(2+m) b^(2n-1)是四次单项式,
∴2+m+2n-1=4,
∴m+2n=3,
m²n-m²-m(4n+mn)-(-2n)²
=m²n-m²-4mn+m²n-4n²
=-m²-4mn-4n²
=-(m+2n)²
=-3²
=-9
由已知得2+m+2n-1=4
∴m+2n=3
∴m²n-m²-m(4n+mn)-(-2n)²
=m²n-m²-4mn-m²n-4n²
=-(4n²+4mn+m²)
=-(m+2n)²
=-3²
=-9