已知-2a^mbc^2与4a^3b^nc^2是同类项求多项式3m^2n-2mn^2-m^2n＋mn^2的值

已知-2a^mbc^2与4a^3b^nc^2是同类项求多项式3m^2n-2mn^2-m^2n＋mn^2的值
已知-2a^mbc^2与4a^3b^nc^2是同类项求多项式3m^2n-2mn^2-m^2n＋mn^2的值

已知-2a^mbc^2与4a^3b^nc^2是同类项求多项式3m^2n-2mn^2-m^2n＋mn^2的值
-2a^mbc^2与4a^3b^nc^2是同类项
则,字母a的次数相等,字母b的次数相等
即, m=3 ,n=1 ,
3m^2n-2mn^2-m^2n＋mn^2
=3×3²-2×3×1²-3²+3×1²
=27-6-9+3
=15