若3a^m-1 bc^2和-2a^3 b^n-2 c^2是同类项,则3m^2 n-2mn^2+2m^2 n+4mn^2-mn的值是
问题描述：
若3a^m-1 bc^2和-2a^3 b^n-2 c^2是同类项,则3m^2 n-2mn^2+2m^2 n+4mn^2-mn的值是
答
3a^m-1 bc^2和-2a^3 b^n-2 c^2是同类项
m-1=3,1=n-2
m=4,n=3
3m^2 n-2mn^2+2m^2 n+4mn^2-mn
=5m^2n+2mn^2-mn
=mn(5m+2n-1)
=4*3*(5*4+2*3-1)
=12*25
=300