已知2xmy2与-3xyn是同类项,求m_(m2n+3m_4n)+(2m2n-3n)的值.
问题描述：
已知2xmy2与-3xyn是同类项,求m_(m2n+3m_4n)+(2m2n-3n)的值.
今天就要看到答案啊,
答
∵2xmy2与-3xyn是同类项,
∴m=1,n=2,
∴m_(m2n+3m_4n)+(2m2n-3n)
=m-m2n-3m+4n+2m2n-3n
=m²n-2m+n
=1²×2-2×1+2
=2