-2MN-3MN-MN+2M-2M-M+3N-2N-4N=?
问题描述:
-2MN-3MN-MN+2M-2M-M+3N-2N-4N=?
写出过程
答
原式=(-3-2-1)MN+(2-2-1)M+(3-2-4)N
=-6MN-M-3N